BEIRUT (AP) — Thousands of people took to the streets in Beirut Thursday for the funeral of Saleh Arouri, top commander of the militant Palestinian group Hamas, who was killed earlier this week in an apparent Israeli airstrike in the Lebanese capital.

Draped in Palestinian and Hamas flags, Arouri’s coffin along with those of two of his comrades were first taken to a Beirut mosque for prayers before being carried to the Palestine Martyrs Cemetery where top Palestinian officials killed by Israel over the past five decades have been buried. Arouri’s automatic rifle was placed on his coffin at the prayer service.

Palestinian officials, including top Hamas official Moussa Abu Marzouk, as well as representatives of some Lebanese political groups attended the funeral. People tried to touch the coffins that were surrounded by Hamas members wearing green caps, some of whom were armed.

“The enemy is running away from its failures and defeats (in Gaza) to Lebanon,” Hamas top leader Ismail Haniyeh said in a speech aired during the funeral. He added that Arouri’s killing in Beirut “is proof of (Israel’s) bloody mindset.”

Lebanese officials and state media said an Israeli drone fired two missiles Tuesday at an apartment in Beirut’s southern Musharafieh district, a stronghold of Lebanon’s powerful Hezbollah group instantly killing Arouri along with six other Hamas members, including military commanders.

Arouri, who was the deputy political head of Hamas and a founder of the group’s military wing, had been on Israel’s radar for years. Israeli Prime Minister Benjamin Netanyahu had threatened to kill him even before Hamas carried out its deadly surprise attack on Israel on Oct. 7 that triggered the ongoing brutal war in Gaza.

Israel had accused Arouri, 57, of masterminding attacks against it in the West Bank, where he was the group’s top commander. In 2015, the US Department of the Treasury dubbed Arouri a Specially Designated Global Terrorist, offering $5 million for information about him.

Arouri’s killing raises tensions in the already volatile Middle East with Israel’s ongoing ground offensive in Gaza, daily exchange of fire between Israeli troops and Lebanon’s Hezbollah fighters, and Yemen’s Iran-backed Houthi rebels attacking ships passing through the Red Sea.

On Wednesday, Israeli airstrikes on southern Lebanon killed nine Hezbollah members, including a local commander, in one of the highest death tolls for the group since the fighting along the Lebanon-Israel border began on October 8. Since then, Hezbollah has lost 143 fighters.

On Thursday, an airstrike on the Iraqi capital Baghdad killed a high-ranking commander of an Iran-backed group. The group accused the US of being behind the attack. An American official, speaking on condition of anonymity because he wasn’t permitted to speak publicly, confirmed that the US military carried out the strike.

In a speech Wednesday evening, Hezbollah leader Sayyed Hassan Nasrallah promised revenge, repeating his group’s statement that “this dangerous crime” of Arouri’s killing will not go “without response and without punishment.” But he specified neither when or how this would happen.

Nasrallah said Hezbollah had so far been careful in its strategic calculus in the conflict, balancing “the need to support Gaza and to take into account Lebanese national interests.” But if the Israelis launch a war on Lebanon, the group is ready for a “fight without limits.”

“They will regret it,” he said. “It will be very, very, very costly.”