In a major development in the Middle East war, reports are increasing that the leader of Hezbollah, Hassan Nasrallah, was killed in an Israeli strike Friday afternoon at the organization’s Beirut headquarters — a development that, if confirmed, could have a major impact on the war. 

The Israeli air force used bunker-busting bombs to obliterate the deeply dug construction at the Dahiyeh district of the Lebanese capital shortly after Prime Minister Netanyahu completed a speech at the United Nations. Hebrew-language press reports this evening were citing security and military officials who expressed confidence that Nasrallah, as well as his closest confidante, Tsai a-Din, were at the bunker when the Israel Defense Force hit it.

The IDF’s Arabic-language spokesman warned residents of the Dahiyeh to stay away from buildings that he mapped out, saying that they belong to Hezbollah. The warning seemed to indicate that Israel would follow up with strikes at buildings that according to intelligence house missiles and rockets.

“In the next hours we will strike three buildings at the Dahiyeh,” the IDF chief spokesman, Rear Admiral Daniel Hagari, told reporters. He named the buildings, which he said are used to warehouse missiles that threaten shipping lanes. He warned residents to leave these sites.

There has so far been no official Israeli confirmation, however. Piles of rubble ensured that identification of casualties would take time, but the Israeli sources say that anyone in the bunker could not have survived. In the immediate aftermath of the bombing, several Iranian, Lebanese, and Arab press reports said that Nasrallah survived the attack. 

Yet an Al-Jazeera Beirut reporter who posted that claim on X later deleted the posting. “Contact with Nasrallah has been completely cut off,” a Lebanese security source told Sky News Arabia, citing an unidentified Hezbollah source. 

“Israel crossed all the red lines,” the Islamic Republic of Iran’s supreme leader, Ali Khamenei, said in a statement. Israelis were bracing for possible retaliatory assaults. The Houthis are threatening to respond to the Beirut attack. In the last few days Iraqi militias launched several missiles at Israel as well. Iran might well attempt a retaliation. 

Mr. Netanyahu authorized the hit prior to his UN speech. His office released a photo that apparently showed him consulting at his New York hotel with top military officials at home. “If you strike us, we will strike you,” he warned Tehran in his speech, in a line that could have been added after the strike authorization. “There is no place in Iran that the long arm of Israel can not reach.”

Nasrallah is a “legitimate target,” Israel’s ambassador at the UN, Danny Danon, told reporters as the Security Council gathered late Friday for an emergency session. Axios reported that the decision to go after the high-profile Hezbollah chief was made once Israel realized that Nasrallah insisted on linking the terror group’s attacks on Israel to the end of the war in Gaza. 

If so, Jerusalem might be hoping for a better chance to negotiate a deal to ensure the safe return of more than 70,000 Israelis to their Galilee homes. Washington and Paris have made an effort, along with several other countries, to impose a 21-day cease-fire in Lebanon in order to allow for talks that would promote the return of Israelis and Lebanese civilians near the border. 

Israeli officials maintained that they had updated American counterparts shortly before the Beirut strike. “The United States had no knowledge of or participation in the IDF strike in Beirut,” President Biden was quoted by Barak Ravid of Axios as saying. “This is a very sensitive moment,” Secretary Blinken said, adding, “how Israel defends itself matters.”