As its forces fiercely attacked fallen Libyan leader Muammar Gaddafi's last two bastions, Sirte and Bani Walid, the interim government claimed Sunday the fighting could end next week.

Soldiers of Libya's National Transitional Council (NTC) prepare for the battle with Gaddafi loyalists in Bani Walid, Libya, Oct. 9, 2011. The head of the ruling Libyan National Transitional Council (NTC) Mustafa Abdel-Jalil said Sunday that it is possible to end the battles next week in Bani Walid and Sirte, the only remaining strongholds of fallen leader Muammar Gaddafi. [Hamza Turkia/Xinhua]

The head of the National Transitional Council (NTC) Mustafa Abdel-Jalil said the battles in Bani Walid, some 180 km south of the capital, had entered its "last phase," with fighters laying siege to the town from all sides.

An NTC commander in the region said the same day NTC fighters had taken over Bani Walid's airport, which has been a stumbling block for the attackers due to its difficult geography.

Jalil also confirmed the NTC's unremitting assaults on Gaddafi's hometown, Sirte, about 450 km east of Tripoli.

The fight has been a bloody one with the local hospital saying Saturday at least 18 people were killed and about 300 wounded in two days since Oct. 7.

After seizing a key road Saturday, the NTC made further major progress Sunday by taking control of the Ouagadougou conference center in downtown Sirte, a focus of heavy fighting in recent days, and a hospital and a university at the main entrance to southeastern Sirte.

Jalil said the fighters were still trying to root out pockets of Gaddafi loyalists and the many snipers, who are reportedly shooting indiscriminately at anything that moves on the street.

Meanwhile, the United States and its NATO allies were considering an end to its six-month bombing campaign that has backed the successful rebel push against Gaddafi.

U.S. defence secretary Leon Panetta said in Naples Thursday NATO was weighing whether to halt their air strikes, adding it would greatly depend on NTC's ground forces in the region.

He also said NATO would keep striking until Gaddafi's loyalists laid down their weapons and the interim government secured the whole country.

Panetta raised a four-point guideline for halting the raids, including Sirte's situation, an end to Gaddafi forces' attacks on civilians, ending his ability to command fighters and the NTC securing the country.

However, on the same day, the Syria-based Arrai television released an audio message from the ousted Libyan leader, who has remained at large since NTC forces entered Tripoli on Aug. 23.

Gaddafi called on Libyans to take to the streets in their millions with their green flags peacefully and bravely, saying the current conditions in Libya were "unacceptable."

He also warned leaders of the developing countries who had recognized the NTC would face a similar fate as him.

Meanwhile, the humanitarian situation in Sirte has worsened, with civilians fleeing in panic in the face of the bombardment by NTC forces and NATO air strikes and heavy casualties among NTC fighters and Gaddafi loyalists.

The UN issued a statement Friday calling for no revenge attacks in Sirte if it is captured by the Libyan interim government while NATO Secretary General Anders Fogh Rasmussen said he believed NTC forces "will do all they can to prevent a humanitarian disaster."