The heaviest fighting of the month-long conflict is under way about five to 10 kilometers inside Lebanon, where Israeli troops early Thursday moved toward the town of Marjayoun near the Litani River.
On Wednesday Israel's cabinet authorized the army to push north to the Litani, which is about 20 kilometers from the border.
While some Israeli troops did move into Lebanon overnight, Israeli officials such as Foreign Minister Tzipi Livni say the bulk of the invasion force will not proceed for a few days to allow more time for United Nations diplomats trying to reach a ceasefire deal.
Livni says it is important to allow diplomatic efforts to continue as part of the effort to get Hezbollah militants to leave southern Lebanon.
