Calling on Hamas to avenge his death and the killing of five other members of the Palestinian resistance group on Tuesday, the mourners gathered at a mosque to recite the prayer of the dead before marching to Shatila refugee camp, the site of an infamous Israeli massacre of hundreds of Palestinians in 1982, where three of them were to be buried.

The coffins of the three, Aruri, Azzam Al-Aqraa of the Hamas military wing Ezzedine Al-Qassam Brigades, and Mohammad Al-Rais, were draped in Palestinian and Hamas flags.

A machine gun was laid on top of each coffin and heavy gunfire rang out as the funeral procession made its way to the cemetery, drowning out chants of "Allahu Akbar" (God is Greatest) by mourners waving Palestinian flags.

"Abu Obeida, bomb Tel Aviv," the mourners shouted, addressing the Gaza spokesman of the Hamas military wing by his nom de guerre.

Aruri and the six other Hamas members were killed in a strike in a south Beirut stronghold of Hezbollah.

Hamas and Lebanese security officials accused Israel of launching the attack, with one high-level Lebanese security official saying they were targeted by guided missiles.

A US defence official told AFP on Wednesday that Israel was behind the attack. Israel has not claimed any responsibility.

Aruri is the most senior Hamas figure to be killed since the Israeli war on Gaza broke out on 7 October.

"The assassination of Saleh Al-Aruri and of any other Palestinian is a failed act because the resistance will continue to produce new leaders," one of the mourners, Oman Ghannum, told AFP.

The 35-year-old Palestinian said he wanted to take part in the funeral procession "to denounce the genocide underway in Gaza and the violation of Lebanese sovereignty by Israel".

Hezbollah leader Hassan Nasrallah warned Israel in a speech on Wednesday against starting a war in Lebanon, vowing that his group would fight back without restraint.

Several Hamas figures in exile reside in Lebanon, under the protection of Hezbollah.

Since the war began, there have been near-daily exchanges of fire between Israel and Hezbollah in the border area.

Tuesday's strike that killed Aruri was the first on the Lebanese capital since hostilities began.