Gaddafi and several of his sons are still at large more than seven weeks after rebel fighters stormed the capital and ended his 42-year rule. His supporters hold Sirte and the town of Bani Walid, south of Tripoli.

Government forces who had for three weeks been pinned down by artillery and rocket fire on the eastern edges of Sirte have since advanced several kilometers (miles) into the city, capturing the southern district of Bouhadi.

Bullet-holed cars carrying terrified, ill and hungry civilians crawled out of Sirte. Aid agencies say they are concerned about civilians who are trapped inside the city by the fighting and running out of food, water, fuel and medicine.

Commanders of forces loyal to the ruling National Transitional Council (NTC) are talking of a "final" push to take the town. Backed by NATO warplanes, they have been bombarding pro-Gaddafi positions inside Sirte.

US Defense Secretary Leon Panetta said he expected NATO aerial operations over Libya to continue while fighting goes on, but that the alliance would discuss the issue this week.

NATO renewed the mission in September for 90 days but agreed to review conditions every 30 days to see whether operations could be ended.