BEIRUT — An Israeli airstrike Monday in a Damascus neighborhood killed a high-ranking Iranian general, Iranian state media said.

Iranian officials and allied militant groups in the region vowed revenge for the killing but did not immediately launch any retaliatory strike.

The killing of Seyed Razi Mousavi, a longtime adviser of the Iranian paramilitary Revolutionary Guard in Syria, comes amid ongoing fears of the Israel-Hamas war sparking a regional spillover. Iran-backed groups in Yemen, Lebanon, Syria and Iraq have launched attacks on Israel and its allies in support of Hamas.

Clashes along the Lebanon-Israel border between Hezbollah and Israel have continued to intensify, with daily exchanges of missiles, airstrikes and shelling across the frontier.

In the Red Sea, attacks by Houthi rebels in Yemen against ships they believe to be connected to Israel have disrupted trade and prompted the launch of a U.S.-led multinational naval operation to protect shipping routes.

Iran-backed militias in Iraq operating under an umbrella group dubbed the Islamic Resistance in Iraq have also launched more than 100 attacks on bases housing U.S. troops in Iraq and Syria, which they have said are in retaliation for Washington’s support of Israel.

The group claimed an attack on a U.S. base next to the commercial airport in Irbil in northern Iraq on Monday. A U.S. military official, speaking on condition of anonymity in accordance with regulations, confirmed the attack and said it had caused injuries but did not provide further details.

Israeli strikes killed two other generals earlier this month in Syria.

Israel on Monday struck the Sayida Zeinab neighborhood, located near a Shiite Muslim shrine, Iran’s official news agency IRNA and Britain-based opposition war monitor the Syrian Observatory for Human Rights said. IRNA described Mousavi as a close companion of Gen. Qassim Soleimani, the head of Iran’s elite Quds Force who was slain in a U.S. drone strike in Iraq in January 2020.

Neither the Israeli military nor Syrian state media immediately issued a statement about Monday’s attack. Israeli officials declined to comment.

Iran Threatens Retaliation

Iran’s President Ebrahim Raisi in a statement said that Mousavi was “martyred while serving as an adviser for the resistance front, defending holy shrines in Syria as well as safeguarding Islamic ideals.” He threatened that the “Israeli regime will definitely pay for this crime.”

Hossein Akbari, Iran’s ambassador to Syria, condemned the killing, saying that Mousavi was in Syria as a “formal military advisor.”

“(Israel) will definitely get a response to this crime at the right time and the right situation,” Akbari said, speaking from Damascus.

Though IRNA didn’t provide other details about the attack, the Syrian Observatory for Human Rights said the Israeli military targeted Mousavi after he entered a farm in the area, which allegedly was one of several offices for Hezbollah. The Lebanese militant group, alongside Iran and Russia, has played a key military role in keeping President Bashar Assad’s government in power throughout the Syrian conflict.

Hezbollah in a statement called Mousavi “one of the best of brothers who worked to support the Islamic Resistance in Lebanon for decades of his honorable life.”

Israel has carried out hundreds of strikes on targets inside government-controlled parts of war-torn Syria in recent years. It doesn’t usually acknowledge its airstrikes on Syria. But when it does, Israel says it’s targeting Iran-backed groups there that have backed Assad’s government.