"Two Israeli enemy strikes, on a truck and a motorbike, in the town of Yohmor al-Shaqeef in the Nabatieh district killed four people," a ministry statement said.

It later reported that an "Israeli enemy airstrike on the town of Safad al-Battikh, in the Bint Jbeil district, resulted in two fatalities and 17 injuries".

Israel's military said it "eliminated" three Hezbollah operatives on Saturday who were driving "a vehicle loaded with weapons", as well as another one riding a motorcycle, and two more armed members of the group elsewhere.

It also said it identified two projectiles launched from Lebanon, decrying "a blatant violation of the ceasefire understandings" by Hezbollah, and later intercepted another "suspicious aerial target".

Hezbollah, meanwhile, said it targeted an Israeli army vehicle in south Lebanon in retaliation for the attack on Yohmor al-Shaqeef.

Israel says it reserves the right to respond militarily to imminent threats under the terms of the ceasefire.

US President Donald Trump had announced on Thursday that a 10-day ceasefire in Lebanon that began on April 17 had been extended for three weeks.

Tehran-backed Hezbollah drew Lebanon into the Middle East war on March 2 by firing rockets at Israel to avenge the death of Iran's supreme leader Ali Khamenei in US-Israeli strikes.

The state-run National News Agency (NNA) reported Israeli artillery shelling on several south Lebanon locations on Saturday.

It also reported a "violent explosion" in Khiam, a strategic town along the east of Lebanon's border with Israel where the agency has previously said the Israeli army has been "systematically" destroying houses and other buildings.

An AFP correspondent saw a huge cloud of smoke billowing over the town.

Israel's military on Saturday reissued a warning to residents not to return to dozens of south Lebanon locations within the so-called "yellow line", which demarcates a ribbon of Lebanese territory around 10 kilometres (six miles) wide running along the length of the border.

Israeli attacks have killed at least 2,496 people in Lebanon since March 2, according to authorities.

On Friday, Hezbollah lawmaker Ali Fayad said the group maintained the right to respond to any Israeli aggression, adding that extending the ceasefire "makes no sense" in light of the continued "hostile acts".