Threats from Israeli officials to unleash Gaza-level destruction on Lebanon are "wholly unacceptable", the U.N. said Tuesday, and warned that "deliberately attacking civilians or civilian objects amounts to a war crime".

Israel has stepped up strikes and deployed ground troops to its northern neighbor since March 2, when Lebanon was dragged into the Middle East war after Tehran ally Hezbollah attacked Israel with rockets in retaliation for the killing of Iranian supreme leader Ali Khamenei.

Youssef Assaf was in a Lebanese Red Cross ambulance when it was targeted by an Israeli strike near Tyre, in southern Lebanon. The 35-year-old paramedic died of his wounds two days later.

"I was called around 10:30 pm and told that he was wounded and in the hospital," his wife, Jeanne d'Arc Boutros, told AFP from northern Lebanon, where she had fled to a relative's home.

Lebanon transferred more than 130 Syrian detainees to their home country on Tuesday, a Lebanese judicial official told AFP, as part of an agreement the two sides signed in February.

Overcrowded Lebanese prisons host more than 2,200 Syrians held on various charges.

Israeli Defense Minister Israel Katz said on Tuesday that Iran's powerful national security chief Ali Larijani was "eliminated last night", along with the commander of Tehran's Basij paramilitary force.

"I have just been updated by the Chief of Staff that Larijani, Secretary of the Supreme National Security Council, and the head of the Basij -— Iran's central repression apparatus -— (Soleimani), were eliminated last night," Katz said in a statement released by his ministry.

Israeli airstrikes rained down on three neighborhoods in Beirut's southern suburbs early Tuesday, Lebanese state media reported, as Lebanon said more than one million people had been displaced in two weeks of fighting.

Lebanon was drawn into the Middle East war on March 2 when Tehran-backed Hezbollah militants attacked Israel in response to the killing of Iranian supreme leader Ayatollah Ali Khamenei in U.S.-Israeli strikes.

In southern Lebanon's Ain Ebel, close to the border with Israel, Suad Jallad holds a poster of her son, killed by Israel last week, saying she would rather be buried next to him than leave.

Israeli President Isaac Herzog told AFP on Monday that an offer by French leader Emmanuel Macron to host direct talks with Lebanon was "a very positive development".

The leaders of five Western countries said in a joint statement Monday that a large-scale Israeli ground operation in Lebanon "must be averted."

NATO allies and other Western nations pushed back Monday on U.S. President Donald Trump's demand that military alliance members help reopen the Strait of Hormuz, the critical conduit for crude oil Iran has effectively closed.

Turkey on Monday condemned Israel's ground operation in Lebanon, cautioning against "another humanitarian catastrophe" unfolding in the Middle East.