For decades, Israel and Iran have fought a shadow war across the Middle East, trading attacks by land, sea, air and in cyberspace.

Crowds at the funeral procession for Maj. Gen. Qassim Soleimani in Tehran, Jan. 6, 2020.

Iran has largely used foreign proxies to strike Israeli interests, while targeted assassinations of Iranian military leaders and nuclear scientists have been a key part of Israel’s strategy.

Israel’s strike in the Syrian capital, Damascus, that killed three top Iranian commanders Monday was the most brazen attack in years, raising fears of a wider confrontation. That would be particularly dangerous in a region already in turmoil on multiple fronts, including Israel’s war in the Gaza Strip, cross-border skirmishes between Israel and the Lebanese militant group Hezbollah and attacks by Yemen’s Houthi militia against Western interests in the Red Sea. An escalation between Israel and Iran would also risk further entangling the United States, given the presence of U.S. troops in the region.

Here are some key moments in the yearslong conflict.

January 2020: A Major Target

The assassination of Gen. Qassem Soleimani, commander of the foreign-facing arm of Iran’s Revolutionary Guard, in a U.S. drone strike in Baghdad was greeted with satisfaction in Israel.

Iran hit back by attacking two bases in Iraq that housed U.S. troops with a barrage of missiles, injuring about 100 U.S. military personnel.

U.S. officials accused Soleimani of causing the deaths of hundreds of soldiers during the Iraq War. They also said that he was behind destabilizing Iranian activities throughout the Middle East and that he was accused of plotting attacks against U.S. embassies and Israeli targets.

The general had built a network of allied militias to defend Iran’s interests across the Middle East and to counter the United States and Israel.

October 2023: Tit-for-Tat Strikes Before Oct. 7

Iran and Israel reportedly carried out a number of covert attacks and counterattacks in the years following Soleimani’s death.

Israel killed Iran’s top nuclear scientist, Mohsen Fakhrizadeh, in November 2021, and followed up with the assassination of a Revolutionary Guard commander, Col. Hassan Sayyad Khodaei, in May 2022.

In July 2021, an oil tanker managed by an Israeli-owned shipping company was attacked off the coast of Oman, killing two crew members, according to the company and three Israeli officials.

Two of the officials said the attack appeared to have been carried out by several Iranian drones that crashed into living quarters underneath the ship’s bridge. Iran did not explicitly claim or deny responsibility, but a state-owned TV channel described the attack on the ship as a response to an Israeli strike in Syria.

Once Israel’s bombardment of Gaza began after the Hamas-led attacks on Oct. 7, Iranian-backed militias stepped up their attacks.

December 2023: Another High-Profile Killing

At the end of last year, Iran accused Israel of killing a high-level military figure, Brig. Gen. Seyed Razi Mousavi, in a missile strike outside Damascus. A senior adviser to the Revolutionary Guard, Mousavi was described as having been a close associate of Soleimani and was said to have helped oversee the shipment of arms to Hezbollah.

Israel, adopting its customary stance, declined to comment directly on whether it was behind Mousavi’s death.

January 2024: Back-and-Forth Attacks Ratchet Up

The Pentagon launched a drone strike in Baghdad that killed a senior figure in an Iran-linked militant group.

The attack came days after an explosion in a suburb of Beirut that killed Saleh Arouri, a Hamas leader, along with two commanders from that group’s armed wing. The blast was the first such assassination of a top Hamas official outside the West Bank and Gaza in recent years.

Officials from Hamas, Lebanon and the United States ascribed the attack to Israel, which did not publicly confirm involvement.

Arouri was the most senior Hamas figure to be killed since Israel vowed to destroy the organization after Oct. 7.

Hezbollah, which receives major support from Iran, stepped up its assaults on Israel after Arouri’s death. Israel’s military hit back at Hezbollah in Lebanon, killing a number of the group’s commanders.

Later in January, Iran accused Israel of launching an airstrike on Damascus. A number of senior Iranian military figures were killed, including the head of intelligence in Syria for the overseas arm of the Revolutionary Guard and his deputy, according to the Iranian news media and an Israeli defense official.

Then, a drone strike by an Iran-backed militia killed three U.S. service members and injured at least 34 others in Jordan. Ten days later, U.S. forces launched a retaliatory drone strike in Baghdad that killed a senior militia leader that U.S. officials blamed for the attacks on U.S. personnel.

February 2024: Further Strikes by Israel

The United States’ retaliatory airstrikes against Iran-backed militias appeared to temper Iran’s actions.

Israel was blamed for a number of attacks in Syria and Lebanon. In February, Syrian state news media said Israel was behind an airstrike on a residential building in Damascus that killed two people.

The Israeli military declined to comment on that strike, though it has acknowledged hundreds of past strikes on Iran-linked targets in Syria.

But the Israeli military did acknowledge a strike in southern Lebanon in February that it said killed a Hezbollah commander, and in March, it killed a senior Hamas operative in an airstrike also in southern Lebanon.

March 2024: A Tense Atmosphere

An Israeli drone strike targeted a car in southern Lebanon, killing at least one person. Israel’s military said it had killed the deputy commander of Hezbollah’s rocket and missile unit. Hezbollah acknowledged the death of a man, Ali Abdulhassan Naim, but did not provide further details.

The same day, airstrikes killed soldiers near Aleppo, in northern Syria, in what appeared to be one of the heaviest Israeli attacks in the country in years.

Those strikes killed 36 Syrian soldiers, seven Hezbollah fighters and a Syrian from a pro-Iran militia, according to the Syrian Observatory for Human Rights, a British-based group that tracks Syria’s civil war.

Israel’s military did not claim responsibility. However, the country’s defense minister, Yoav Gallant, wrote on social media, “We will pursue Hezbollah every place it operates and we will expand the pressure and the pace of the attacks.”

Three days later, on Monday evening, Israeli warplanes struck the building in Damascus in the attack that killed the three top Iranian commanders.

No US involvement in strike on Iran's Damascus mission, White House says

An excavator clears rubble after a suspected Israeli strike on Iran's consulate, in Damascus.

The United States on Tuesday said it was not involved in an Israeli airstrike on Iran's embassy compound in the Syrian capital of Damascus that killed two Iranian generals and five military advisers.

White House national security spokesman John Kirby dismissed as "nonsense" Iranian charges of U.S. responsibility for Monday's bombing, and he warned that Washington would respond to any retaliatory attacks.

"Let me make it clear. We had nothing to do with the strike in Damascus," he told a briefing. "We weren't involved in any way."

The Damascus strike threatened to escalate the years-long confrontation between Israel and Iran and its proxy militias that have intensified since fighting erupted in October between Israel and Iran-backed Hamas Islamists in the Gaza Strip.

In response to U.S. support for Israel, Iran-backed militias have targeted U.S. military bases in Iraq, Syria and Jordan, although there have been no such attacks since early February following U.S. retaliatory strikes.

"We always take our force protection very seriously, to protect our troops, our facilities in Iraq and Syria," said Kirby. "We will do whatever we need to do to protect those troops."

Pentagon spokesperson Sabrina Singh said Israel provided no advance warning of the strike on the Iranian mission in the Syrian capital.

"We were not notified by the Israelis about their strike or the intended target of their strike in Damascus," Singh told a briefing, adding that Iran had been privately told the U.S. was not behind the strike.

Shortly before the attack, Israel notified the United States that it would be operating in Syria, but used vague language that did not identify a target, two officials said on condition of anonymity.

Israel "did not include any details on who they were targeting or where it would be conducted, and the strike was already under way before word could be passed through the U.S. government," said one official.

Iran on Tuesday said it would retaliate against Israel for the strike that destroyed its embassy's consular section and killed seven members of Iran's Quds Force, an elite contingent of the Revolutionary Guards Corps that conducts paramilitary and espionage operations outside Iran.

Israel has not claimed responsibility for the attack.