The Israeli military confirmed Tuesday that it was building a wall along a one-kilometre section of the border with Lebanon, which it said was to reinforce an older security fence.
The wall, which will have an average height of five metres, was to protect the area against sniper fire and other attacks by militants on the Lebanese side of the border, army spokesman Major Arye Shalicar told dpa.
"There was already a fence, but the fence didn't prevent frictions between the sides," he said.
It is to run westward from Israel's northern-most community of Metula toward the Lebanese village of Kfar Kila, he added.
The project had been fully coordinated with the United Nations Interim Force in Lebanon (UNIFIL) and with the Lebanese Army, Shalicar said.
There had been a number of recent incidents, which did not result in injuries, between "enemy organizations" and Israeli soldiers guarding the border, he said, without giving any further details.
Lebanese television on Monday showed bulldozers and construction workers on the Israeli side of the border, near the southern passageway of the Lebanese Fatima Gate, a closed border crossing to Israel.
Media first reported in January that Israel planned to construct the wall.
The Lebanese army and UNIFIL have set up road blocs to prevent anyone from reaching the area. A Lebanese security official told dpa the army was on alert.
In 2006, Israel and the Lebanese Shiite movement Hezbollah fought a devastating month-long war, which killed 1,200 people in Lebanon, mainly civilians, and 160 Israelis, mostly soldiers.