A powerful airstrike killed 11 people in central Beirut on Saturday, the Lebanese civil defence said, shaking the capital as Israel pressed its offensive against the Iran-backed Hezbollah group.

The attack destroyed an eight-storey building and caused a large number of fatalities and injuries, Lebanon's National News Agency said. Footage broadcast by Lebanon's Al Jadeed station showed at least one destroyed building and several others badly damaged around it.

Israel used bunker buster bombs in the strike, leaving a deep crater, the agency said. Beirut smelled strongly of explosives hours after the attack.

The blasts shook the capital around 4 a.m. local time. Security sources said at least four bombs were dropped in the attack.

It marked the fourth Israeli airstrike this week targeting a central area of Beirut, in contrast to the bulk of Israel's attacks on the capital region, which have hit the Hezbollah-controlled southern suburbs. Last Sunday, an Israeli airstrike killed a Hezbollah media official in the Ras al-Nabaa district of central Beirut.

Rescuers searched through rubble, in an area of the city known for its antique shops.

A man whose family was hurt tried to comfort a traumatized woman outside a hospital. Car windows were shattered.

"There was dust and wrecked houses, people running and screaming, they were running, my wife is in hospital, my daughter is in hospital, my aunt is in the hospital," said the man, Nemir Zakariya, who held up a picture of his daughter.

"This is the little one, and my son also got hurt — this is my daughter, she is in the American University (of Beirut Medical Centre), this is what happened."

Israel launched a major offensive against Hezbollah in Lebanon in September, following nearly a year of cross-border hostilities ignited by the Gaza war, pounding wide areas of Lebanon with airstrikes and sending troops into the south.

Israeli strikes killed at least 62 people and injured 111 in Lebanon on Thursday, bringing the toll since October 2023 to 3,645 dead and 15,355 injured, Lebanon's Health Ministry said. The figures do not distinguish between combatants and civilians.

Hezbollah and the Lebanese government accuse Israel of indiscriminate bombing that kills civilians. Israel denies the allegation and says it takes numerous steps to avoid the deaths of civilians.

Hezbollah strikes in the same period have killed more than 100 people in northern Israel and the Israeli-occupied Golan Heights. They include more than 70 soldiers killed in strikes in northern Israel and the Golan Heights and in combat in southern Lebanon, according to Israel.

The conflict began when Hezbollah, Tehran's most important ally in the region, opened fire in solidarity with its Palestinian ally Hamas after it launched the Oct. 7, 2023 attack on southern Israel.

A U.S. mediator travelled to Lebanon and Israel this week in an effort to secure a ceasefire. The envoy, Amos Hochstein, indicated progress had been made after meetings in Beirut, before going to meet Israeli Prime Minister Benjamin Netanyahu and Defence Minister Israel Katz.