(Adds Israeli, UN statements) (Adds detail, background)
BEIRUT, Dec 15 (Reuters) - A Lebanese soldier fired at an Israeli on the border between the two countries on Sunday, Lebanese security sources and the Israeli army said.
The Lebanese sources said they had lost contact with the Lebanese soldier after the shooting, which took place at the western tip of the border region across which Israel and the Lebanese Hezbollah militia fought a 34-day war in 2006.
"A sniper from Lebanese Armed Forces opened fire at a civilian vehicle travelling on the Israeli side," an Israeli army spokesperson said, without giving details of any casualties.
The U.N. peacekeeping force in southern Lebanon said they had been informed about "a serious incident" at the border.
"We are now trying to determine the facts of what happened and the situation is ongoing," UNIFIL spokesman Andrea Tenenti said. "UNIFIL's force commander is in contact with counterparts in the Lebanese and Israeli army, urging restraint."
Tenenti said that both sides were cooperating with UNIFIL after the incident, which he said appeared to have happened on the Israeli side of the Blue Line dividing Lebanese and Israeli forces.
(Reporting by Dominic Evans in Beirut and Ari Rabinovitch in Jerusalem; Editing by Andrew Heavens)