Israeli air strikes hit a Palestinian group's compound in Lebanon near the border with Syria early on Sunday, the latest in a series of moves against Iran's allies in the Middle East.
There were “three hostile strikes” by drones after midnight in Lebanon’s mountains near Qusaya town, “where the Popular Front for the Liberation of Palestine-General Command has military posts”, the state-run NNA news agency reported.
The group is loyal to the government of Syrian President Bashar Al Assad.
“MK planes targeted one of our sites with three small rockets. There were no casualties, only material damage,” an official from the Palestinian faction in Qusaya said.
The PFLP-GC is a militant nationalist group with close links to Syria and Iran, which split from the Marxist-Leninist Popular Front for the Liberation of Palestine in the 1960s.
The Israeli army and Lebanese authorities have yet to comment.
A day earlier, two drones, which the Lebanese army and the Iran-backed Hezbollah group said were Israeli, crashed in the Hezbollah-dominated southern suburbs of Beirut.
One of the two drones was booby-trapped and exploded after hitting a Hezbollah media office, the group’s spokesman, Mohammed Afif, said on Sunday.
The second landed but did not explode.
Hezbollah on Tuesday said the drone that crashed in its Beirut stronghold at the weekend contained an explosive device weighing more than five kilograms.
"We confirm that the purpose of this first drone was not reconnaissance but the carrying out of a bombing attack," the movement said in a statement.
The US was quick to stand by Israel after the attacks, saying the country should be able to defend itself from threats to its security.
On Twitter, US Vice President Mike Pence said he had a call with Israeli Prime Minister Benjamin Netanyahu on Monday.
"The United States fully supports Israel's right to defend itself from imminent threats," Mr Pence said. "Under President Trump, America will always stand with Israel."
Lebanon’s President Michel Aoun said yesterday that the two drone incursions into Lebanese territory were a “declaration of war”.
Mr Aoun said that his country had a right to defend its territory.
“We are a people who want peace, not war, and we don’t accept anyone threatening us in any way,” he tweeted.
Mr Aoun met the UN special co-ordinator for Lebanon, Jan Kubis, yesterday to discuss the “Israeli assault on the southern suburbs of Beirut”, his office said on Twitter.
Prime Minister Saad Hariri met Lebanon’s interior and defence ministers and the army chief yesterday to discuss security issues, his office said.
Mr Hariri was more cautious in his reaction to the Israeli incursions.
“The Lebanese government sees it best to avoid any sliding of the situation towards a dangerous escalation but this requires the international community affirming its rejection of this blatant violation,” he told the ambassadors of the UN Security Council’s five permanent members.
Iran-backed Hezbollah warned Israeli soldiers at the border to expect a response.
Its leader, Hassan Nasrallah, said in Beirut on Sunday that “there won’t be any spot in Israel that will be safe” if Israeli planes entered Lebanese airspace again.
“I tell people who live in the north and everyone in occupied Palestine, they can’t live a single moment safely,” Nasrallah said. “We won’t allow anyone to violate our sovereignty.”
He said any Israeli drones that flew over Lebanon would be shot down.
Nasrallah said the Israeli drone attack was the first since Hezbollah fought a month-long war with Israel in 2006. He described it as “very, very dangerous”.
On Sunday, Mr Hariri said the Israeli reconnaissance flights over Beirut were a clear breach of the UN resolution that ended the 2006 war.
The resolution banned all unauthorised weapons between the Litani River and the Blue Line, the UN-monitored border between Israel and Lebanon.
Mr Hariri said friends of Lebanon had a responsibility to protect UN Security Council Resolution 1701 “from the dangers of Israeli violations and their repercussions”.
On Saturday night, Israel admitted it had launched a pre-emptive attack against an Iranian base near the Syrian capital Damascus to thwart a drone strike.
But Nasrallah said Israel had actually aimed at Hezbollah and killed two of its fighters.
“If Israel kills any of our brothers in Syria, we will respond in Lebanon,” he said.
The NNA reported that its army had intensified patrols along the Blue Line.
It said that Israeli planes were flying lower than usual above the south of the country.
Nasrallah accused Israeli Prime Minister Benyamin Netanyahu of orchestrating the attacks to gain popularity before the September legislative elections.
“Netanyahu is preparing his elections with your blood,” he told his audience.
