Israeli "soldiers operating in southern Lebanon identified an immediate threat against them. The soldiers responded with fire toward the threat. An initial examination indicates that during the incident, a hit was identified on a UNIFIL post, located approximately 50 meters (yards) from the source of the threat, resulting in the injury of two UNIFIL personnel," the statement said.

It came after the UN mission said two of its peacekeepers were injured after explosions close to an observation tower at its Naqura headquarters.

It was the second incident of its kind reported by UNIFIL in two days, after two other Blue Helmets were injured on Thursday, sparking global condemnation.

Hours before Friday's incident, "the IDF instructed UNIFIL personnel to enter into protected spaces and remain there. This instruction was in place at the time of the incident," the military added.

The statement came shortly after the military said it was "conducting a thorough review" to determine details of attacks on UN peacekeepers in southern Lebanon, after the four mission members were injured.

"The IDF expresses deep concern over incidents of this kind and is currently conducting a thorough review at the highest levels of command to determine the details," the military said.

UN peacekeepers patrolling the Lebanese side of the border with Israel have been thrust into the violence of the Israel-Hezbollah war that has killed more than 1,200 people in Lebanon, according to an AFP tally of Lebanese health ministry figures, and displaced a million others.