Israel says it carried out multiple strikes on Hezbollah's Beirut headquarters 

Israel's military carried out a series of targeted strikes Friday on the central headquarters of the Hezbollah terror organization in the Beirut suburb of Dahiyeh, flattening buildings and sending huge plumes of smoke above the city.

In a televised statement, Israel Defense Forces (IDF) said the strike targeted what the spokesperson called the epicenter of Hezbollah's terror, which he said had been intentionally built beneath residential buildings in the heart of Dahiyeh. Lebanon's Health Ministry said at least six people were killed and 91 were wounded.

The target was the group's leader, Hassan Nasrallah, news outlets reported, citing sources who requested anonymity to discuss the attacks. The Israeli army declined to comment. Whether Nasrallah was in the headquarters was not immediately clear, and Hezbollah did not comment.

Israeli sources said the U.S. had been notified moments before the airstrike, but Secretary of Defense Lloyd Austin said that the United States had no advance warning nor was it involved in the Israeli operation in Beirut.

"As you know this operation took place just a few hours ago, and they're still making assessments, so I don't have any further information or specifics for you at this time," he said. "You've heard me say a number of times, an all-out war should be avoided."

Lebanese television carried footage of the strike's aftermath, with billowing smoke and the smoldering ruins of the building with rubble filling the streets around it.

IDF spokesperson Rear Admiral Daniel Hagari went on to say, after nearly a year of Hezbollah firing rockets and drone attacks into their country, "Israel is doing what every sovereign state in the world would do if they had a terror organization that seeks their destruction on their border."

The initial wave of Israeli strikes came about an hour after Israeli Prime Minister Benjamin Netanyahu finished addressing the United Nations General Assembly in New York. His office circulated a photograph of him on the telephone during the approval of the attack.

Israeli Ambassador Danny Danon told reporters that he could not confirm whether the Hezbollah leader was present during the strike, which he said was aimed at a "meeting of bad people" who were plotting an attack against Israel.

Shortly after midnight in Beirut, the Israeli military said it had contacted residents in three buildings in Dahiyeh to immediately evacuate because they are near "Hezbollah's strategic assets." Local media reported strikes had resumed in the southern suburbs of Beirut.

At the General Assembly, Netanyahu had a message for Iran, which sponsors both Hezbollah in Lebanon and Hamas in Gaza.

"If you strike us, we will strike you," he said. "There is no place — there is no place — in Iran that the long arm of Israel cannot reach. And that's true of the entire Middle East."

The U.N. secretary-general called for calm.

"We must avoid a regional war at all costs," Antonio Guterres said. He urged both Israel and Hezbollah to accept a 21-day cease-fire proposal put forward by the U.S. and France and backed by several countries.

"We need this cease-fire now," Guterres said. "We cannot afford endless negotiations, as we have on Gaza."

Prior to the airstrike on the Beirut suburb, Israel and Hezbollah had continued to exchange fire across Lebanon's southern border. Earlier Friday, at a news conference, acting Lebanese Health Minister Firass Abiad said Israeli airstrikes had continued overnight, killing 25 people and injuring an unspecified "large number" of others in the country.

Hezbollah fired rockets into the northern Israeli city of Tiberias, saying it was responding to "savage" strikes on Lebanese towns and villages. First responders in the city reported that three people suffered minor injuries.

In Geneva, U.N. humanitarian officials said the burgeoning conflict is having broader regional consequences.

The U.N. refugee agency's representative in Syria, Gonzalo Vargas Llosa, said more than 30,000 people have crossed the border from Lebanon into Syria in the past 72 hours due to the fighting. He said perhaps 75% to 80% of them are Syrians returning home. About 1.5 million Syrian refugees are in Lebanon, fleeing their own civil war.

The U.N. humanitarian coordinator in Lebanon, Imran Riza, told reporters, "We are witnessing the deadliest period in Lebanon in a generation, and many expressed their fear that this is just the beginning."

The U.N. on Friday released $10 million from its emergency humanitarian fund to help meet needs in Lebanon.

U.N. Correspondent Margaret Besheer and reporter Natasha Mozgovaya contributed to this report. Some information for this report came from The Associated Press, Reuters and Agence France-Presse.