Shells fired by the Israeli army fell in a border town in south Lebanon overnight Wednesday, Lebanon's state media reported.
No casualties or injuries were reported.
"Remnants of heavy illumination shells fired by the Israeli enemy at night towards Lebanese territory were found in Bastra Farm in the liberated Shebaa Farms," Lebanon's National News Agency confirmed.
The UN's Interim Force in Lebanon (Unifil) said it was investigating the incident in the town of Wadi Khansa, in south Lebanon's Hasbaya district, after reports one of the shells had landed on a house which was under construction. Local media also reported that three other shells fell on a residential area.
"Our troops are on the ground to look into it and see whether we can verify the information. We are there with the [Lebanese army]," said Unifil spokesman Andrea Tenenti.
An Israeli Army statement said the rounds were fired towards Mount Dove, where Israel runs a military camp in the Lebanese-occupied Shebaa farms, during a routine military activity.
"The possibility that part of a projectile fell and hit a residence inside Lebanese territory is being looked into," the Israeli military statement said. "The incident is under review."
The incident comes amid Israeli reports that Israeli Prime Minister Benjamin Netanyahu has had repeated discussions with defence officials concerning accelerating readiness for a possible strike on Iran — the backer of Lebanon's Hezbollah party and paramilitary.