Earlier, it had said six people were killed, a further 14 people were injured, with four still being treated in hospital.

This was followed by a statement by a Hezbollah-linked Islamic health organisation which said seven of its staff, including two medics, were killed in the attack.

Middle East latest: IDF strikes Beirut

The airstrike in the Bachoura district of the Lebanese capital targeted an apartment in a building that houses an office of the Health Society, a group of civilian first responders affiliated to Hezbollah.

It was close to Lebanon's parliament and the United Nations headquarters.

It comes after Iran launched dozens of missiles into Israel on Tuesday night.

It was the second airstrike to hit central Beirut this week and the second to directly target the Health Society in 24 hours.

Footage and images of the blast emerged as Israel's military said it had killed 15 Hezbollah militants in south Lebanon today.

In a statement on Telegram, the Israel Defence Forces (IDF) said the fighters were killed in a strike on a municipality building in Bint Jbeil - where it said the Iran-backed militant group was operating and storing large quantities of weapons.

It added that the Beirut bombing was a "precise" strike - after its forces suffered their deadliest day on the Lebanese front in a year of clashes with Hezbollah.

Israel has mostly concentrated its airstrikes in south and eastern Lebanon, as well as the southern suburbs of Beirut, where Hezbollah has a strong presence.

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It issued an urgent warning to more than 20 towns in southern Lebanon on Thursday, with IDF spokesman Avichay Adraee urging residents to evacuate the areas immediately.

"Hezbollah's activities force the IDF to act forcefully against it," he said.

"The IDF does not intend to harm you, so for your safety, you must evacuate your homes immediately and head north of the Awali River. Save your lives."

The IDF also announced the deaths of eight of its soldiers killed in Lebanon and named and released images of them.

Hezbollah and Iran's other regional allies, Yemen's Houthis and armed groups in Iraq, have launched attacks in the region in support of Hamas in its war with Israel in Gaza.

Israeli military claimed on Thursday that Rawhi Mushtaha, the head of the Hamas government in Gaza, had been "eliminated" alongside senior security officials Sameh al Siraj and Sami Oudeh in strikes three months ago.

It said Hamas did not announce their deaths after the attack to "prevent loss of morale and the functioning of its terror operatives".

Fighter jets struck an underground compound that served as a command centre, where the militants were "hiding", it added.

It claimed Mr Mushtaha was one of Hamas's "most senior operatives" and had a direct impact on decisions relating to where fighters were deployed.

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More UK government-chartered flights to bring Britons home from Lebanon are due to take place today, the Foreign Office has announced.

It said the flights will depart from Beirut-Rafic Hariri International Airport, and will continue for as long as the security situation allows.

Yesterday, more than 150 British nationals were flown out of the country, landing in Birmingham last night.