Troops loyal to Libya's new rulers advanced at least eight kilometres (five miles) towards Muammar Gaddafi's hometown of Sirte in heavy fighting today, commanders said.
One government soldier was killed and two wounded, while at least one of Gaddafi's men lost his life, they added.
The fighting east of Sirte brought fighters of the National Transitional Council (NTC) to within less than 80 kilometres (50 miles) of the city, one commander told AFP.
"The clashes were very intense," another commander, Mustafa Bendardaf, said.
"Five enemy vehicles were taken out. Three were destroyed in NATO air strikes and two were captured by our men," he said.
An AFP correspondent behind the frontline heard intense artillery exchanges throughout the day.
Another NTC commander, Adel Semfez, said that the fighting had been sparked by a reconnoitre launched at dawn by a unit led by famed rebel commander Selim Nabus, which had ambushed a pro-Gaddafi convoy destroying four vehicles and capturing a fifth.
"It was a fairly routine engagement for this front line," he added, stressing that it did not mark the launch of a major offensive on Sirte.