A rescuer fights the blaze amid the smouldering rubble of a building destroyed in an Israeli air strike in the Haret Hreik neighbourhood of Beirut's southern suburbs on Friday. AFP

The strikes were the most powerful yet seen in the Lebanese capital the past year, leveling six buildings and sending massive clouds of orange and black smoke billowing in the skies.

Lebanon’s state-run National News Agency said 10 teams from the Lebanese Red Cross arrived to the scene of the strike. There was no immediate word on casualties in the strike.

The Israeli army spokesman, Rear Adm. Daniel Hagari, said it targeted the main Hizbollah headquarters, located beneath residential buildings. Hizbollah’s Al Manar TV said buildings were reduced to rubble in the blast, so powerful it rattled windows and shook houses some 30 kilometres north of Beirut.

Not long before the explosion, thousands were massed in a Beirut suburb for the funeral of three Hizbollah members, including a senior commander, killed in earlier strikes.

Lebanese Prime Minister Najib Mikati urged the international community to "stop" Israel from waging a "genocidal war" against Lebanon, following a huge Israeli strike on Beirut's southern suburbs.

"This new Israeli aggression proves that the Israeli enemy doesn't care about all the international efforts and calls for a ceasefire," Mikati, who is in New York, said in a statement issued by his office, urging the international community to stop the "genocidal war that it (Israel) is waging on Lebanon".

Agencies