Israel has acknowledged that shots fired by its military injured two UN troops in southern Lebanon.
The Israeli Defence Forces (IDF) said it struck the United Nations Interim Force in Lebanon (Unifil) base on Friday when troops identified an “immediate threat against them” nearby and opened fire.
It said the incident would be investigated “at the highest levels”.
Unifil said its headquarters in the town of Naqoura, near the Israeli-Lebanese border, had been affected by explosions for the second time in 48 hours.
On Thursday, two Indonesian soldiers were injured falling from an observation tower after an Israeli tank fired towards it.
UN Secretary-General Antonio Guterres condemned yesterday’s attack, saying that it was “intolerable and cannot be repeated”.
Israeli ground forces launched a ground invasion into southern Lebanon last month as they escalated their response to rocket fire from the Lebanese armed group Hezbollah.
Hezbollah and Israel have been trading near-daily cross-border fire since last October, when the Palestinian armed group Hamas attacked communities in southern Israel.
The IDF said the UN post in Naqoura was about 50m away from the source of the threat identified by soldiers. It said it had told peacekeeping troops to stay in protected spaces at the time, and added that it was continuing to examine the incident.
Unifil meanwhile also said Israeli military vehicles had knocked over barriers at another Unifil site in Labbouneh, closer to the border with Israel.
The incidents represented a “serious development”, it said.
Lebanon’s Prime Minister Najib Mikati said Friday’s attack was “a crime which is directed at the international community”.
The UK government said it was “appalled” by reports of attacks on UN positions.
A Downing Street spokesperson told reporters on Friday: “It is vital that peacekeepers and civilians are protected.”
On Thursday, Unifil said an IDF Merkava tank fired at an observation tower at its headquarters in Naqoura. Two peacekeepers suffered minor injuries but remain in hospital, it said.
The IDF said it had fired at the base after ordering personnel stationed there to remain in “protected places”.
In Thursday’s statement, Unifil said its positions in southern Lebanon had been “repeatedly hit” in the fighting. It highlighted one incident in which IDF soldiers fired on one of its positions in Labbouneh, near the Israeli border, “hitting the entrance to the bunker where peacekeepers were sheltering, and damaging vehicles and a communications system”.
Unifil spokesperson Andrea Tenenti told the BBC that Thursday’s incident was “very concerning” as while there had previously been “exchanges of fire” in the region, “this time it looks more of a deliberate attack against our troops”.
“We are still trying to ask the Israeli authorities for some explanation of what happened,” he said.
Israel argues that Unifil has failed to stabilise the region, and has asked peacekeepers to withdraw northwards so it can confront Hezbollah.
The Israeli ambassador to the UN, Danny Danon, reiterated his nation’s call for Unifil personnel to withdraw north by 5km (3 miles) to “avoid danger” – but UN peacekeeping chief Jean-Pierre Lacroix said they would remain in position in line with their UN mandate.
Mr Danon said Israel was “fulfilling our obligation” to a 2004 UN resolution calling for the disbanding of Lebanese and non-Lebanese militant groups.
He also called for Lebanon’s armed forces to be deployed to the south to “do the job”.
About 10,000 peacekeepers from 50 countries are stationed in Lebanon, alongside around 800 civilian staff.
Since 1978, they have patrolled the area between the Litani River and the UN-recognised boundary between Lebanon and Israel – known as the “Blue Line”.
Hezbollah began firing rockets into northern Israel on 8 October last year, the day after Hamas’s deadly attack on southern Israel. The Iran-backed group says it is acting in solidarity with the Palestinians and has said it will stop firing if there is a ceasefire between Israel and Hamas in Gaza.
Over the past three weeks, Israel has dramatically escalated its campaign against Hezbollah, intensifying air strikes against southern Lebanon and southern parts of Beirut, assassinating Hezbollah’s leader Hassan Nasrallah and launching a ground invasion.
Lebanon says more than 2,000 people have been killed, mainly in the recent escalation, and hundreds of thousands have been displaced. This week Hezbollah rocket fire has killed two Israeli civilians and a Thai national, Israeli authorities say.