Libyan fighters advanced on remaining strongholds loyal to Moammar Gadhafi, as a delegation headed to Niger on Friday to demand it turn over one of the ousted leader's sons. The delegation will ask Niger to hand over Saadi Gadhafi and other regime officials who fled to the country, said Mustafa Abdul Jalil, chairman of the National Transitional Council. Saadi Gadhafi arrived in Niger on Sunday, accompanied by eight regime officials "of minor importance," Niger Justice Minister Marou Amadou said this week. At least three Libyan convoys have entered Niger recently, carrying generals, family members and low-ranking Gadhafi regime military and security personnel, according to officials in Niger. Gadhafi and the others were "accepted on a humanitarian basis," Amadou said. As the new government demands their return, loyalists are targeting the last remaining strongholds. Bani Walid residents have been fleeing after being given 48 hours to leave ahead of an attack. The deadline passed Thursday night, though it was not immediately known whether forces loyal to the National Transitional Council launched an assault on the city southeast of Tripoli. Meanwhile, troops loyal to the NTC pushed into the heart of Gadhafi's hometown of Sirte on Thursday before pulling back to the outskirts for the night, NTC military spokesman Ali Gheliwan said. Fighters faced rocket fire from Gadhafi loyalists during the assault on the town that sits on the Mediterranean coast, Gheliwan said. Eleven NTC fighters were killed and 34 wounded in the assault that saw troops capture 40 pro-Gadhafi fighters, he said. In southern Libya, convoys of NTC pickup trucks loaded with arms and ammunition barreled toward Sabha -- and the nearby towns of al-Birak and al-Qira. Al-Qira is the hometown of Gadhafi's brother-in-law and intelligence chief Abdullah Al-Senussi. Al-Senussi is wanted by the International Criminal Court for alleged crimes against humanity, along with Gadhafi and his son Saif al-Islam Gadhafi. Fighting was fierce in communities outside Sabha. Two NTC fighters were killed and 22 wounded, and nine pro-Gadhafi fighters were captured, said Abdelssalam Khamis, head of the NTC medical mission around Sabha. Thursday's renewed fighting comes on the eve of an anticipated vote at the U.N. on a draft Security Council resolution that would establish a United Nations Support Mission in Libya. According to the draft, the mission's mandate would be to help Libya extend state authority, protect human rights, support justice and take steps needed to get the nation back on its feet economically. The anticipated vote by the Security Council comes the same day Turkey's Prime Minister Recep Tayyip Erdogan was expected to visit Tripoli. Meanwhile, French President Nicolas Sarkozy and British Prime Minister David Cameron vowed Thursday to help Libya's interim leaders hunt down the ousted Libyan leader. Cameron and Sarkozy are the most senior Western leaders to visit Libya since the start of the uprising. France and Britain played pivotal roles in NATO's aerial bombing campaign against forces loyal to Gadhafi, "Let us be clear. This is not finished," Cameron said during a visit to Tripoli. "We will help you find Gadhafi and bring him to justice." Cameron said he did not know the whereabouts of Gadhafi or his family, but "the very clear message is that they should all give themselves up and they should all face justice."