Hezbollah leader Hassan Nasrallah was killed in an Israeli airstrike last year while inside the militant group's war operations room, according to new details Sunday disclosed by a senior Hezbollah official.

A series of Israeli airstrikes flattened several buildings in Beirut’s southern suburbs on Sept. 27, 2023, killing Nasrallah. The Lebanese Health Ministry said six people died. According to news reports, Nasrallah and other senior officials were meeting underground.

The assassination of Nasrallah, who had led Hezbollah for 32 years, turned months of low-level strikes between Israel and the militants into all-out war that battered much of southern and eastern Lebanon for two months until a U.S.-brokered ceasefire took effect Nov. 27.

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“His Eminence (Hassan Nasrallah) used to lead the battle and war from this location,” top Hezbollah security official Wafiq Safa told a news conference Sunday near near the site where Nasrallah was killed. He said Nasrallah died in the war operations room. He did not offer other details.

Lebanese media had reported that Safa was a target of Israeli airstrikes in central Beirut before the ceasefire but appeared unscathed.

During the first phase of the ceasefire, Hezbollah is supposed to move its fighters, weapons and infrastructure away from southern Lebanon north of the Litani River, while Israeli troops that invaded southern Lebanon need to withdraw all within 60 days. Lebanese army soldiers are to deploy in large numbers and alongside United Nations peacekeepers be the sole armed presence in southern Lebanon.

Lebanon and Hezbollah have been critical of ongoing Israeli strikes and overflights across the country and for only withdrawing from two of dozens of Lebanese villages it controls. Israel says that the Lebanese military has not done its share in dismantling Hezbollah infrastructure.

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Hezbollah’s current leader Naim Kassem in a televised address Saturday warned that its fighters could strike Israel if its troops don’t leave the south by the end of the month.

Safa said that Parliament Speaker Nabih Berri, who negotiated the ceasefire deal with Washington, told Hezbollah that the government will meet with U.S. envoy Amos Hochstein soon. “And in light of what happens, then there will be a position,” said Safa.

Hochstein had led the shuttle diplomacy efforts to reach the fragile truce.