History of Iran-Israel Tensions

Since the 1979 Islamic revolution, Iran’s conflict with Israel has gradually evolved geographically and strategically. By 2019, hostilities no longer played out in a shadow war. Iran had deployed men, money and/or materiel to aid allies on three of Israel’s borders—Lebanon, Syria and the Palestinian territories. Both Iran and Israel also warned of direct conflict. 

For more than four decades, all of Israel’s major military campaigns played out with one of Iran’s allies, partners or proxies.

  • 1982 to 2000: Hezbollah during and after Operation Peace for Galilee 
  • 1987 to 1993: Hamas and Islamic Jihad during the Palestinians’ First Intifada
  • 2000 to 2005: Hamas and Islamic Jihad during the Palestinians’ Second Intifada
  • 2006: Hezbollah during the Second Lebanon War  
  • 2008 to 2009: Hamas and Islamic Jihad during Operation Cast Lead
  • 2012 - ongoing: Hezbollah, Revolutionary Guards and other Iranian-backed militias during the Syrian civil war
  • 2012: Hamas and Islamic Jihad during Operation Pillar of Defense 
  • 2014: Hamas and Islamic Jihad during Operation Protective Edge
  • 2021: Hamas and Islamic Jihad during Operation Guardian of the Walls
  • 2022: Islamic Jihad during Operation Breaking Dawn
  • 2023: Islamic Jihad during Operation Shield and Arrow
  • 2023: Hamas and Islamic Jihad during Operation Swords of Iron

In September 2019, Major General Hossein Salami, commander of Iran’s elite Islamic Revolutionary Guard Corps (IRGC), boasted, “We have managed to obtain the capacity to destroy the impostor Zionist regime.” Destroying Israel was now an “achievable goal.”

By 2019, Iran’s proxies increasingly acted like a network spread across the Middle East in ways that boosted Tehran’s influence and threatened Israel’s security. Militias born under Iranian supervision in one country deployed on other nations’ battlefields. Lebanon’s Hezbollah operated in Syria and Iraq and as far afield as Yemen, where its operatives trained Houthi rebels. Along the way, Iran’s allies gained battlefield experience and shared their knowledge and experience with younger generations.

At the end of 2019, Israel Defense Forces (IDF) Chief of Staff Lieutenant General Aviv Kochavi said that the IDF was preparing for the “possibility” of a “limited confrontation” with Iran. The IDF carried out both overt and covert operations against Iran and its allies, particularly to prevent the spread of precision missiles from Iran. “We will not allow Iran to entrench itself in Syria or in Iraq,” he said in December. He warned of the potential magnitude of a new conflict. “In the next war, be it with the north or with Gaza, the intensity of enemy firepower will be great,” he said. “I’m looking at everyone in the eye, it will be intense.”

Prime Minister Benjamin Netanyahu alleged that the Iranian threat to Israel extended as far as Yemen. “Iran hopes to use Iran, Iraq, Syria, Lebanon and Yemen as bases to attack Israel with statistical missiles and precision-guided missiles. That is a great, great danger,” he warned.

By 2020, the IDF’s top three objectives all centered on the Islamic Republic: 

•    Preventing Iran from obtaining a nuclear weapon 
•    Disrupting Hezbollah’s precision missile project 
•    Stopping Iranian entrenchment in the wider region

regional map


History of Relations 

Iran’s relationship with Israel wasn’t always so fraught. After Israel gained independence in 1948, the two nations developed ties for strategic and economic reasons. In the 1950s, as part of Prime Minister David Ben-Gurion’s “periphery doctrine,” Israel began to cultivate relationships with non-Arab states and ethnic minorities. The 22 Arab countries opposed to Israel were predominantly Sunni, so Iran – which was predominantly Persian and Shiite – seemed to be a logical partner.  

Both countries also had strong relations with the United States and opposed Soviet efforts to gain influence in the region. Iran became the biggest importer of Israeli arms, while Iran exported oil to Israel. Israel had a diplomatic mission in Tehran. For three decades, between 1948 and 1978, relations were amicable.  

Relations ruptured abruptly after the monarchy was ousted in 1979. The new theocratic regime labeled the United States the “Great Satan” and Israel the “Little Satan.” The regime abandoned Israel and embraced the Palestinian cause as its own; it announced a new holiday, Qods (Jerusalem) Day. In August 1979, revolutionary leader Ayatollah Ruhollah Khomeini invited all Muslims to observe the last Friday of Ramadan as a day of solidarity with the Palestinian people—“to join together to sever the hand of this usurper and its supporters.” The Qods Force, the IRGC’s elite unit for operations outside Iran, was also named after Jerusalem.

Ayatollah Ruhollah Khomeini (right) with son Ahmad Khomeini (left) and successor Ayatollah Ali Khamenei (center)) in 1981

Iran considered Israel to be an occupier of lands holy to and long governed by Muslims. “As I have often warned both before and after the revolution, I once again remind everyone of the danger of the prevalent, festering and cancerous Zionist tumor in the body of Islamic countries,” Khomeini told a group of pilgrims.  

Iran also promoted the Palestinian cause to enhance its revolutionary credentials among Arabs and the wider Muslim world. Iranian leaders argued that the Middle East governments abdicated their responsibility to the Palestinians. Egypt signed peace a treaty with Israel in 1979; Jordan followed suit in 1994.


The First Decade

Tensions deepened after Israel invaded Lebanon in 1982 for two reasons. Operation Peace for Galilee sought to force the Palestinian Liberation Organization, Iran’s ally, out of Lebanon. It also impacted the Shiite community that lived in southern Lebanon and had a centuries-long connection to Iran. Tehran dispatched some 1,500 IRGC advisers to Lebanon’s eastern Bekaa Valley. They didn’t confront Israel, but they mobilized, trained and equipped an underground militia that evolved into Hezbollah. Hezbollah symbolized Iran’s grand strategy to create proxy forces across the Middle East to promote Iran’s interests and ideology.

After the PLO was forced to pull out of Beirut in 1982, Hezbollah gradually assumed the mantle of chief resistance force against Israel. The IRGC remained in Lebanon to assist; it funded and armed its surrogate. Under Iran’s tutelage, Hezbollah launched a guerrilla war, including suicide bombings, against Israeli forces in the south. Lebanon became the most dangerous front line for Israel—and the forward outpost for Iran.

In 1983, Hezbollah pioneered the use of suicide bombings to expel Western and Israeli forces from Lebanon. The first bombing against Israel was on Nov. 4, 1983, when a car laden with 600 kilograms of explosives drove into IDF headquarters in southern Tyre. It killed 28 Israelis. Under growing attack, Israel withdrew from a large chunk of Lebanon in June 1985. It maintained a military presence in a “security zone” controlled by its ally, the South Lebanon Army.

Encouraged by Israel’s retreat, Hezbollah stepped up the pace of attacks. During the second half of 1985, Hezbollah carried out at least a dozen suicide bombings. “These bombings were unambiguous political and military messages that Israeli soldiers would continue to die until their withdrawal from Lebanon was complete,” according to a U.S. Army study.

Hezbollah, still in the underground, issued its first manifesto in 1985. “Our primary assumption in our fight against Israel states that the Zionist entity is aggressive from its inception, and built on lands wrested from their owners, at the expense of the rights of the Muslim people. Therefore, our struggle will end only when this entity is obliterated. We recognize no treaty with it, no cease-fire, and no peace agreements, whether separate or consolidated.” It echoed precisely the language out of the Islamic Republic.

Hezbollah flag
Hezbollah's logo (above), which includes a bare hand holding up a rifle and a globe, is similar to the IRGC's logo

Yet Iran and Israel maintained covert connections when mutually beneficial. During the 1980s, after Iraq invaded Iran, Tehran imported weapons and military supplies from Israel in covert operations that eventually involved the Reagan administration in the Iran-Contra Affair in 1986. The transfers were exposed and ended, also partly because Iran failed to pay on time. 


The Second Decade

With Iranian aid and funding, Hezbollah increased its presence in Lebanon by moving beyond its covert military role to become a political party. In 1992, it emerged from the underground to run in the first parliamentary elections since the civil war. It won eight out of 128 seats. The presence of an Iranian ally in the government of a country on the Mediterranean gave it important influence and access – to other parts of the region as well as the West—far from its own borders.

Throughout the 1990s, Hezbollah continued to engage in low intensity warfare with the IDF and the South Lebanon Army. In 1993, Israel launched Operation Accountability—a seven-day campaign—to retaliate for the deaths of Israeli soldiers and to pressure the Lebanese government to rein in Hezbollah. The Shiite militia countered by firing rockets into Israel. After tensions along the border heightened in 1996, Israel launched Operation Grapes of Wrath against Hezbollah. Neither ended Hezbollah’s attacks.

By 2000, more than 900 Israeli soldiers had died in Lebanon; thousands of Lebanese and Palestinian civilians were killed. The war became increasingly controversial in Israel, where it was often compared to America’s long and costly campaign in Vietnam. In May 2000, Israel voluntarily withdrew from southern Lebanon. It was the first time Israel ceded Arab territory without a peace treaty.

“This is the first glorious victory in 50 years of Arab-Israeli conflict,” Hezbollah leader Hassan Nasrallah told his followers in Beirut. Supreme Leader Ayatollah Ali Khamenei congratulated Hezbollah for being at the “frontline of the struggle of the Muslim world with the Zionists.” Israel’s most potent regional foes were no longer in the Sunni Arab world. They were Hezbollah and its creator, Iran.

Soleimani, Nasrallah and Khamenei in 2000
Qods Force commander Qassem Soleimani, Hassan Nasrallah and Ayatollah Ali Khamenei in Tehran in 2000


The Third Decade

Despite Israel’s withdrawal, Supreme Leader Ayatollah Ali Khamenei described Israel in 2000 as a “cancerous tumor” that “must be uprooted from the region.” Over the next five years, with Iran’s aid, Hezbollah built up its military arsenal, embedded in villages near the Israeli border and dug tunnels across southern Lebanon to facilitate the underground movement of men and arms. Iran and Syria provided thousands of rockets and missiles. Iranian advisers helped prepare strategy for a possible ground war. Clashes occasionally broke out along the border.

Hezbollah also strengthened its political hand. In the 2005 parliamentary election, it won 35 seats—the second largest bloc—and was appointed to government cabinet posts for the first time. Economically, it also became the second largest employer – in clinics, schools, businesses and social services—after the Lebanese government.

In 2006, Hezbollah captured two Israeli soldiers at the border in a plot to demand the release of Palestinian and Lebanese prisoners in Israel. It backfired. Israel responded with a massive air and ground assault. The ensuing 34-day war, Israel’s longest, was costly in life and destruction to both sides; hundreds of thousands were displaced on both sides. Nearly 1,200 Lebanese died; more than 170 Israeli soldiers and civilians were killed.

Hezbollah bunker
The entrance to a Hezbollah bunker discovered by the IDF in 2006

The Second Lebanon War ended in a military draw. In Israel, the war was largely considered a failure. Hezbollah had surprised the IDF with its preparedness, tenacity, tactics and weaponry. Nearly 4,000 rockets and missiles rained down on Israel. But Nasrallah also admitted that he had miscalculated the Israeli reaction to the kidnappings—at a huge cost to his followers and to Lebanon. Large swaths of Beirut were destroyed. Yet he claimed a “divine and strategic victory” since the underdog—a militia that outperformed any Arab state in any earlier war against Israel—needed only to survive to claim a form of victory.

Besides providing weaponry, Iran provided strategic advice and maintained a military presence during the war. Years later, Qods Force commander Qassem Soleimani revealed that he was in Lebanon for all but one day of the conflict. Tehran celebrated Hezbollah’s performance. “You imposed your military superiority over the Zionist regime, consolidated your spiritual dominance in regional and international extent, derided the Zionist army's phony invincibility and splendor and portrayed the usurper regime's fragility,” Khamenei wrote Nasrallah in an effusive letter.  


The Fourth Decade

In 2011, Khamenei outlined Iran’s solution to the Arab-Israeli conflict. “We do not suggest launching a classic war by the armies of Muslim countries, or throwing immigrant Jews into the sea, or mediation by the U.N. and other international organizations,” he said. “We propose holding a referendum with the Palestinian nation. The Palestinian nation, like any other nation, has the right to determine their own destiny and elect the governing system of the country.”

But the same year, Iran’s focus expanded beyond Lebanon and the Palestinians after a civil war erupted in Syria, its closest ally and its route to sustain support for Hezbollah in neighboring Lebanon. Tehran long had a military presence in Damascus, where it ran its Lebanon operations and liaised with militant Palestinian groups. But it was soon sucked into military operations to prop up President Bashar Assad as he lost control over large chunks of the country.

Between 2011 and 2019, Tehran provided military assistance as well as billions of dollars in economic aid. Iran was deploying soldiers by late 2011. Troops – from both the IRGC and the conventional Artesh military—fought rebel groups and jihadi movements. The numbers of Iranians deployed in Syria fluctuated from the high hundreds to the low thousands. Tehran also mobilized an estimated 20,000 fighters from Lebanon, Iraq, Afghanistan and Pakistan to fight in Syria; Hezbollah provided thousands, the largest and longest commitment. By 2019, Iran had a military presence in more than three dozen Syrian bases. Qods Force commander Soleimani was often photographed in Syria.

Members of the Fatemiyoun militia, comprised of Afghans organized by Iran to fight in Syria

Iran used its presence in Syria to open a new front against Israel. It transferred missiles, drones and other weapons that could be used against Israel. Hezbollah did frequent reconnaissance missions in the south and deployed teams on the Golan Heights, where they built missile bases and tunnel networks. 

In 2012, Israel countered with airstrikes on Hezbollah and Iranian targets in Syria that killed senior Iranian military officers, including IRGC generals, and prominent Hezbollah militiamen. Between 2012 and 2017, the Israeli Air Force acknowledged it had carried out nearly 100 strikes on arms convoys bound for Hezbollah. Between 2017 and September 2018, the IDF conducted strikes on more than 200 Iranian targets in Syria. “We struck thousands of targets without claiming responsibility or asking for credit,” Lieutenant General Gadi Eisenkot, the outgoing chief of staff, said in January 2019.

Iran’s responses were usually limited in scope and calibrated to avoid a full-scale war with Israel. But in 2018, Iran began testing the limits of engagement and ended up escalating hostilities. On February 10, Iran launched an explosive-laden drone from the T-4 command center near Palmyra. An Israeli combat helicopter intercepted it, and eight Israeli jets attacked Iranian targets in Syria. One Israeli warplane was hit by Syrian missiles, forcing the pilot and navigator to eject. Israeli air force Brigadier General Tomer Bar described it as the “most significant attack” against Syria since the 1982 Lebanon war.

On May 9, Iranian forces in Syria fired 20 rockets at Israeli military outposts in the Golan Heights. Israel’s Iron Dome aerial defense system intercepted four rockets; the rest did not land on Israeli soil. Jerusalem’s response was swift. The next day, Israeli jets struck an estimated 70 Iranian targets in Syria. It was the largest attack carried out by Israel in Syria since the 1973 Arab-Israeli War.


By mid-2019, Iran had lost at least 500 soldiers in Syria, either fighting against rebels or in Israeli strikes. “The more Iran tries to establish itself on Syrian soil, the deeper it will sink in the Syrian sands,” Israeli Defense Minister Naftali Bennett said in December 2019. “Syria is increasingly becoming Iran's Vietnam.”

Israel was also linked to a least a dozen attacks on Iran’s nuclear program from 2010 to 2021. The first wave, mainly cyberattacks and assassinations of key personnel, was between 2010 and 2012 before the launch of nuclear diplomacy with Iran by the world’s six major powers. The second began in 2018 and included a Mossad raid, an assassination, and explosions.


The Next Decade

For four decades, Iran avoided a full-blown war with Israel over the Palestinians, but it repeatedly warned of serious consequences if Israel attacked the Islamic Republic. “We will raze Tel Aviv and Haifa,” Khamenei said in 2013. Iran’s ability to deploy and build proxies hundreds of miles from its border led to rhetorical bravado. “Any action to start a war in the region will ignite a fire that will burn those who have started the war. If Israel makes a strategic mistake, it has to collect bits and pieces of Tel Aviv from the lower depths of the Mediterranean Sea,” warned Brigadier General Abbas Nilforoushan, the IRGC deputy commander for operations, in September 2019. “Lately, Iran has been threatening Israel with destruction,” Prime Minister Netanyahu said, standing in front an F-35 warplane, in July 2019. “It should remember that these planes can reach every place in the Middle East, including Iran, and of course also Syria.” Israel was reportedly the first country to use the stealth fighter, one of the world’s most advanced warplanes, in an air strike.


For two decades, Qassem Soleimani orchestrated Iran’s operations in the Levant. The IRGC implicated Israel in the U.S. drone strike that killed him in January 2020. “The joy of the Zionists and Americans will in no time turn into mourning,” warned spokesman Ramezan Sharif.

With each decade, hostilities between Iran and Israel intensified and took new forms; Iran amassed a growing array of partners or proxies with ever more sophisticated weapons. The flashpoints also grew in volume and scale.

By the end of the 2010s, Iraqi militias backed by Iran had acquired ballistic missiles capable of reaching Israeli cities. Tehran reportedly has reportedly transferred short-range missiles – with ranges up to 700 km (434 miles) – to Shiite groups in Iraq. In 2019, Israel allegedly conducted seven airstrikes on Iranian weapons depots in Iraq. Iran also helped Houthi rebels in Yemen to develop medium-range missiles with ranges of up to 1448 km (900 miles). The Houthis only needed a range increase of some 200 miles to hit the city of Eilat at Israel’s southern tip. Israel reportedly added missile detection and defense systems facing south in response to Houthi threats to strike Israel in December 2019.

Palestinian groups publicly discussed how Iran provided them with weapons and training. In May 2021, an Islamic Jihad official claimed that his group had purchased rockets “with Iranian money” and had been trained to fire them by Iranian military advisors. “I am proud to say that the rockets that are used to pound Tel Aviv have an Iranian signature on them,” Ramez al Halabi told an Iraqi TV channel. Hamas political leaders also acknowledged receiving support from Iran. “I give thanks to those who provided funds and weaponry to the courageous resistance, the Islamic Republic of Iran, [which] has not skimped in extending funds, weaponry, and technology to the resistance," Ismail Haniyeh said on a Hamas Telegram channel in May 2021.

The gradual unraveling of the nuclear deal—brokered by the world’s six major powers in 2015 —added a combustible element to the already volatile environment. After President Trump withdrew from the deal in May 2018, Iran gradually began breaching its commitments in mid-2019. Netanyahu had repeatedly vowed to take military action, including bombing Iran, to prevent the Islamic Republic from developing the world’s deadliest weapon. 

In April 2021, the Biden administration launched new diplomacy to get both Tehran and Washington to fully comply with the 2015 nuclear deal. The United States attended indirect talks on returning to the agreement hosted by the European Union in Vienna. The talks include the other five world powers – Britain, China, France, Germany and Russia – and Iran. 

Israeli officials reiterated their criticism of the agreement while the talks were underway. “Let there be no mistake, an agreement with Iran will not bind us in any way,” Netanyahu declared in a speech marking Holocaust Remembrance Day on April 7, 2021. Intelligence Minister Eli Cohen warned that a “bad deal will send the region spiraling into war.” Iran “has no immunity anywhere,” he told Reuters on April 29. “Our planes can reach everywhere in the Middle East - and certainly Iran.” 

In 2021, Israel’s top military official announced that funding and preparations for an attack on Iran’s nuclear sites had “dramatically accelerated.” “It’s a very complicated job, with much more intelligence, much more operational capabilities, much more armaments,” Lt. Gen. Aviv Kohavi, then the Israel Defense Forces (IDF) chief of staff, revealed in September. Israel also accelerated the pace and scope of military exercises. In January 2023, Israeli and U.S. forces conducted a four-day exercise in the largest joint military exercise to date. The live-fire drill included 42 Israeli aircraft and 100 U.S. fighters, bombers and other warplanes as well as a U.S. carrier strike group. Some 6,400 U.S. personnel and more than 1,100 Israeli personnel were involved. Between 2022 and 2023, Israel held at least 10 major exercises, including simulations of multifront combat in preparation for a scenario in which Iran’s proxies would launch coordinated attacks.

On Oct. 7, 2023, Hamas and Palestinian Islamic Jihad launched a multi-prong military operation on Israel on Oct. 7, 2023. It included rocket attacks on southern and central Israel, balaclava-clad fighters dropping from paragliders, and the murderous slaughter of civilians in their homes, on city streets and at a music festival in southern and central Israel. It was the boldest and most sophisticated operation by the Palestinian extremist movement.

Iran’s top leaders applauded Hamas for its multi-pronged attack on Israel in public comments, contacts with leaders of the militant factions in Gaza, and in Iranian media. Supreme Leader Ayatollah Ali Khamenei called the unprecedented operation “a devastating earthquake” and a “great calamity” for Israel.

In the initial phase of the war, top U.S. and Israeli officials said Iran was clearly complicit in the attack given its decades of support for Hamas, but both nations said their intelligence had not identified a direct Iranian role. CNN, citing U.S. intelligence, reported that Iranian officials were surprised by the assault.  

Garrett Nada is the managing editor of The Iran Primer at the U.S. Institute of Peace. 


Photo Credits: Khomeini via Khamenei.ir [CC BY (https://creativecommons.org/licenses/by/4.0)]; Bunker by IDF via Flickr (CC BY-NC 2.0)
Some of the information in this article was originally published on January 21, 2020.