The army said the troops were carrying out pinpoint operations against Hizbollah positions near the Israel-Lebanon border.

According to the Ynet news website, Israeli forces had reached the outskirts of the town of Bint Jbeil, which it called a Hizbollah stronghold.

The Maroun al-Ras area, just across the Lebanese border, has been the scene of heavy clashes in recent days.

The conflict began after two Israeli soldiers were captured and eight killed by Hizbollah fighters in a cross-border raid on July 12.

More than 369 people in Lebanon have been killed mostly from Israeli aerial bombardments against Hizbollah positions and some civilian installations.

Rice visit

New Israeli ground incursion in southern Lebanon came as the US secretary of state is on her way to the region in the wake of visits by European envoys.

En route, Condoleezza Rice said the United States' poor relationship with Syria is overstated and indicated an openness to working with Damascus to resolve the crisis in the Middle East.

Rice has tried to walk delicately between supporting the Lebanese government while also not dictating to Israel how it should handle its own security. Her posture has frustrated numerous allies.

"We all want to urgently end the fighting. We have absolutely the same goal," Rice said.

But she added that if the violence ends only to restart within weeks, "then all of the carnage that Hezbollah launched by its illegal activities, abducting the soldiers and then launching rocket attacks, we will have gotten nothing from that."