BEIRUT (AP) The Israeli military said it struck Hezbollahs headquarters in Beirut on Friday in a series of massive explosions that targeted the leader of the militant group and leveled multiple high-rise apartment buildings.

At least six people were killed and 91 were wounded, Lebanons health ministry said. It was the biggest blast to hit the Lebanese capital in the past year and appeared likely to push the escalating conflict closer to full-fledged war.

Hezbollah leader Hassan Nasrallah was the target of the strikes, according to two people familiar with the matter who spoke on condition of anonymity, including one United States official. The Israeli army declined to comment on who it was targeting. It was not immediately clear if Nasrallah was at the site, and Hezbollah did not comment on the report.

The death toll is likely to rise significantly as teams comb through the rubble of six buildings. Israel launched a series of strikes on other areas of the southern suburbs following the initial blast.

After the strikes, Prime Minister Benjamin Netanyahu abruptly cut short a visit to the United States to return home. Hours earlier, he addressed the United Nations, vowing that Israels intensified campaign against Hezbollah over the past two weeks would continue further dimming hopes for an internationally backed cease-fire .

News of the blasts came as Netanyahu was briefing reporters after his U.N. address . A military aide whispered into his ear, and Netanyahu quickly ended the briefing.

Israeli army spokesperson Rear Adm. Daniel Hagari said the strikes targeted the main Hezbollah headquarters, saying it was located underground beneath residential buildings.

The series of blasts at around nightfall reduced six apartment towers to rubble in Haret Hreik, a densely populated, predominantly Shiite district of Beiruts Dahiyeh suburbs, according to Lebanons national news agency. A wall of billowing black and orange smoke rose into the sky as windows were rattled and houses shaken some 30 kilometers (20 miles) north of Beirut.