The United Nations Interim Force in Lebanon (UNIFIL) said two Indonesian peacekeepers were killed "when an explosion of unknown origin destroyed their vehicle". Two other peacekeepers were wounded, one of them seriously.

Also in the south, Lebanon's army said an Israeli strike killed one of its soldiers, while a security source told AFP that three Hezbollah members were killed in an Israeli strike on Beirut's southern suburbs.

Lebanon was pulled into the Middle East conflict when the Tehran-backed armed group fired rockets at Israel on March 2 to avenge the killing of Iran's supreme leader in the opening salvo of the US-Israeli war against the Islamic republic.

Israel has responded with broad strikes across Lebanon and a ground offensive in the south. Lebanese authorities say more than 1,200 people have been killed since the hostilities began.

UNIFIL said it had launched an investigation into Monday's deaths, which came a day after another Indonesian peacekeeper was killed and three others wounded by a projectile, also of unknown provenance, that exploded near a UNIFIL position.

Jean-Pierre Lacroix, UN under-secretary-general for peace operations, strongly condemned "these unacceptable incidents", adding that "all acts that endanger the peacekeepers must stop".

Permanent Security Council member France said it was seeking to a meeting of the body over the matter, while Spain also condemned the deadly attacks.

- 'Direct' attack -

Lebanese President Joseph Aoun condemned "the targeting of peacekeeping forces" in a phone call with UNIFIL's commander.

Aoun "continues to conduct multiple international contacts" in a bid to bring about talks with Israel, a statement from the presidency said.

UN special coordinator for Lebanon Jeanine Hennis-Plasschaert called in a statement for "an immediate truce to stop the devastation".

State media reported Israeli air strikes on south Lebanon, as well as in parts of the adjacent West Bekaa area, cutting roads in the region after Israel's army issued an evacuation warning for several towns there.

The Lebanese army said one of its soldiers was killed in "a direct Israeli attack on an army checkpoint" in the south's Tyre region.

A military source told AFP the strike was the first direct targeting of an army checkpoint since the war began.

The army had previously announced the deaths of eight off-duty soldiers in southern and eastern Lebanon.

- 'Command centres' -

Also Monday, two strikes hit Beirut's southern suburbs, one targeting an apartment in the Bir Hassan district, according to an AFP photographer, who said Hezbollah gunmen then cordoned off the site.

A security source told AFP that three Hezbollah members were killed in the strike and three others wounded.

An eyewitness who declined to be identified said victims were evacuated following the strike, which came after an Israeli army warning for parts of Beirut's southern suburbs, where most residents have fled.

The building is located in a residential neighbourhood packed with shops and commercial establishments, several of which were damaged, the photographer said.

The Israeli military said a strike in Beirut killed the deputy commander of a unit "responsible for coordinating" between Hezbollah and "Palestinian terrorist organisations operating in Lebanon, Gaza, Syria" and the Israeli-occupied West Bank, along with two other operatives from the unit.

Other strikes in Beirut and south Lebanon targeted Hezbollah "command centres", the military said.

Hezbollah, meanwhile, claimed a series of attacks against Israeli targets in south Lebanon and across the border, including one targeting an intelligence base on the outskirts of Tel Aviv.

It said its fighters were engaged in "fierce clashes" with Israeli forces in south Lebanon's Ainata.

The Israeli military said a soldier was killed fighting in south Lebanon, bringing the number of Israeli soldiers killed there to six this month.