The Israeli military insisted in its statement that it “remains committed” to the ceasefire.
Hezbollah said a senior commander was targeted in the strike, without confirming if they were killed.
“The targeting was clearly aimed at a key... figure in the resistance, and the results are unknown,” Hezbollah official Mahmud Qomati told reporters in front of the strike location, saying the attack “crosses a new red line”.
He was speaking before Israel said it had succeeded.
An AFP correspondent at the scene said the strike hit the third and fourth floors of a nine-storey building, where ambulance and fire crews scrambled to find survivors and Lebanese soldiers deployed to secure the site.
Debris littered the road below, with several burned-out cars seen in the street.
The AFP journalist saw rescue workers evacuating a body wrapped in a white bag and at least three wounded women from the site.
“I was on the balcony. There was a flash, then I hit the railing and all the glass broke,” a man who was in a building opposite the targeted apartment told AFP, refusing to give his name.
Lebanon’s official National News Agency said three missiles were fired at the building.
‘Maximum enforcement’
Israeli Prime Minister Benjamin Netanyahu’s office said he had ordered the attack.
“In the heart of Beirut, the IDF [Israeli military] attacked the Hezbollah chief of staff, who had been leading the terrorist organisation’s build-up and rearmament,” the premier’s office said in a statement.
“Israel is determined to act to achieve its objectives everywhere and at all times.”
Separately, Israeli Defence Minister Israel Katz said: “Anyone who raises a hand against Israel will have his hand cut off,” warning that Israel would “continue the policy of maximum enforcement”.
Israel has defended its attacks on Lebanon since the ceasefire as upholding the terms of the deal by preventing Hezbollah from rebuilding.
Sunday’s strike was the first on Beirut’s southern suburbs since June 5, when Israel said it hit a Hezbollah drone factory.
Hezbollah weakened
Hezbollah was weakened by its fight with Israel, which it started in support of its ally Hamas in Gaza in October 2023 with cross-border exchanges of fire that later escalated into two months of full-blown war.
Since then, Lebanon has come under increasing Israeli and US pressure to disarm the militant group, a move that the group has rejected.
“Hezbollah will not be allowed to rearm and operate inside of Lebanon and we expect Lebanon to hold Hezbollah’s feet to the fire on this,” Israeli government spokeswoman Shosh Bedrosian said after Sunday’s strike.
“Hezbollah’s terrorist activities constitute a violation of the understandings between Israel and Lebanon and the IDF will continue to operate to remove any threats to the citizens of Israel,” she told reporters.
Netanyahu earlier on Sunday told a Cabinet meeting that Israel “will continue to do everything necessary to prevent Hezbollah from re-establishing its threat capability against us”.
Lebanese President Joseph Aoun called on the international community to intervene firmly to stop Israeli attacks on the country.
Beirut “reiterates its call to the international community to assume its responsibility and intervene firmly and seriously to stop the attacks on Lebanon and its people”, he said.
-Agence France-Presse
