The Israeli military says it has targeted Hezbollah's central headquarters in Beirut's southern suburbs in an attack that shook the Lebanese capital and sent thick clouds of smoke over the city.
The news outlet Axios cited an Israeli source as saying Hezbollah leader Sayyed Hassan Nasrallah was the target of the strike and that the Israeli military was checking if he was hit.
A source close to Hezbollah told Reuters that Nasrallah is alive while Iran's Tasnim news agency also reported he was safe.
Iran-aligned Hezbollah's al-Manar television reported that four buildings were destroyed and there were many casualties in the multiple strikes, which marked a major escalation of Israel's conflict with Hezbollah.
Al-Manar's live feed showed search and rescue teams scrambling over concrete and protruding metal, with a correspondent for the TV station saying the attack had left several large craters and damaged many surrounding buildings.
The Israeli military said it had carried out a "precise strike" on Hezbollah's headquarters which it said were "embedded under residential buildings in the heart of the Dahiyeh in Beirut".
Israel has struck the Hezbollah-controlled southern suburbs of Beirut, known as Dahiyeh, four times over the last week, killing at least three senior Hezbollah military commanders.
But Friday's attack was far more powerful, with multiple blasts shaking windows across the city, recalling Israeli air strikes during the war it fought with Hezbollah in 2006.
In a televised statement, Israeli military spokesman Daniel Hagari said the central command centre was embedded deep within civilian areas.
The strikes hit Beirut shortly after Israeli Prime Minister Benjamin Netanyahu vowed to continue Israel's attacks on Hezbollah fighters in Lebanon in a closely watched United Nations speech, as hopes faded for a ceasefire that could head off an all-out regional war.
Lebanese Prime Minister Najib Mikati said the attack showed Israel did not care about global calls for a Lebanon ceasefire.
It was by far the most powerful attack carried out by Israel in Beirut during nearly a year of conflict with Hezbollah.
Security sources in Lebanon said the attack targeted an area where top Hezbollah officials are usually based.
The conflict between Israel and Hezbollah has escalated sharply this week, with Israeli air strikes killing more than 700 people in Lebanon.
The escalation has raised fears of an even more destructive conflict between the heavily armed adversaries.
Speaking at the United Nations General Assembly, Netanyahu said: "As long as Hezbollah chooses the path of war, Israel has no choice, and Israel has every right to remove this threat and return our citizens to their homes safely."
"Israel has been tolerating this intolerable situation for nearly a year. Well, I've come here today to say enough is enough," he said.
Several delegations walked out as Netanyahu approached the lectern while supporters in the gallery cheered.
Netanyahu's office said he would cut short his trip to New York following the strike and would return to Israel on Friday.
The United States did not have advanced warning of the Beirut strike and US Defense Secretary Lloyd Austin spoke with his Israeli counterpart as the operation was ongoing, a Pentagon spokesperson said on Friday.
Israel says its campaign aims to secure the safe return home of tens of thousands of people who were forced to flee homes in northern Israel because of rocket attacks Hezbollah has been carrying out in solidarity with its Palestinian ally Hamas, which is fighting Israel in the Gaza Strip.
This week's escalation has displaced about 100,000 people in Lebanon, increasing the total number of people uprooted in the country by the conflict to more than 200,000
with AP
