"The process of transferring authority has begun," an army statement said. It added that more than 50 percent of the areas held by Israel had been transferred to UN forces.

Under a UN-brokered truce, Israel should hand over control of its positions in southern Lebanon to the UN's Interim Force In Lebanon, or UNIFIL, which would then give it to the Lebanese army.

Under the Security Council resolution, the UN force in Lebanon would be enlarged from 2,000 to 15,000 troops.

The withdrawal process "will be carried out in stages and is conditional on the reinforcement of UNIFIL and the ability of the Lebanese army to take effective control of the area," the statement added.

Israeli forces launched attacks in Lebanon five weeks ago after Hezbollah guerillas kidnapped two Israeli soldiers. The offensive has killed more than 1,100 Lebanese people.

On the Lebanese side, government forces have been assembling north of the Litani River not far away from the Israeli border. The troops were to cross the river on Thursday morning to make their first deployment along the Israeli border in nearly 40 years.