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

Israel has responded with large-scale air strikes across Lebanon and a ground offensive in the south. Lebanese authorities say more than 1,200 people have been killed since the hostilities broke out.

On Monday, two strikes hit Beirut's southern suburbs, one of them targeting an apartment in a residential building, according to an AFP photographer, who said Hezbollah gunmen imposed a security cordon at the site after the attack.

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

An eyewitness who declined to be named said victims were evacuated from the site following the strike.

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

The Israeli army, which had issued an evacuation order for the area -- where most residents had already fled -- said it had "begun striking Hezbollah terrorist infrastructure in Beirut".

In south Lebanon, where state media reported a series of Israeli air strikes, the Lebanese army said one of its soldiers was killed and others wounded in an attack on one of its checkpoints in the Tyre region.

A military source told AFP that the strike was the first direct targeting of a Lebanese army checkpoint since the start of the war.

Earlier, the army's command announced the deaths of eight soldiers in the south and east of Lebanon since the war's beginning, although they were not on duty at the time of their deaths.

On Sunday, an Indonesian soldier with the UN's peacekeeping force in Lebanon (UNIFIL) was also killed when a projectile exploded near a UNIFIL position close to the border, while three others were wounded.

The source of the projectile has not yet been determined.

Other UN peacekeepers were wounded on Monday in a separate "incident" near the Lebanese-Israeli border, a spokesperson for the force said, without specifying the nature of the incident.

Hezbollah, for its part, continued to claim attacks against Israeli positions and forces, including on an intelligence base on the outskirts of Tel Aviv.

The Israeli military announced Monday that one of its soldiers was killed fighting in south Lebanon, and another seriously wounded, bringing the number of Israeli soldiers killed in Lebanon to six.