Dozens of Israeli warplanes dropped 23 tonnes of explosives on a Hizbollah bunker in Beirut on Wednesday after intelligence information showed senior leaders of the Shi'ite group were there, military sources said.

Israeli soldiers advance towards southern Lebanon near the northern Israeli village of Avivim Wednesday July 19, 2006. Fierce firefights between Israeli troops and Hezbollah militants erupted Wednesday along Lebanon's southwestern border with Israel, leaving two Israeli soldiers dead, the Israeli army said. [Reuters]

The Israeli Maariv newspaper's NRG Web site said Hizbollah chief Sayyed Hassan Nasrallah was believed to be in the bunker in southern Beirut at the time of the strike.

In Beirut, Hizbollah said none of its leaders were killed.

"Hizbollah denies that any of its leaders or personnel were killed during the latest bombardment ... in the southern suburb," the group said in a statement faxed to Reuters.

The NRG Web site quoted a senior military source, speaking after the raid late on Wednesday, as saying information obtained by security forces had shown Nasrallah was there.

Other Israeli news Web sites said once the military obtained information that senior Hizbollah members were inside the bunker, multiple raids were quickly ordered.

Hizbollah said the building targeted was a mosque under construction and not a bunker housing Hizbollah leaders.

Israel has said no one was immune from attack in the wake of a cross-border raid a week ago when Hizbollah guerrillas abducted two Israeli soldiers and killed eight others.

An Israeli helicopter gunship killed Nasrallah's predecessor, Sheikh Abbas al-Mousawi, in 1992.