It is not known if Col Gaddafi and his family were in Bab al-Aziziya on Tuesday, but the complex is reported to be connected by underground tunnels to various key locations across the city. The Gaddafi family are also believed to have access to numerous safe houses in Tripoli and beyond. The situation is unclear in the colonel's hometown of Sirte, which has been a stronghold of regime loyalists. Reports said retreating government troops were heading there. And rebel leader Mahmoud Jibril, currently in Qatar, warned that there were still places that needed urgent help, such as the southern city of Sebha which is home to many members of Col Gaddafi's tribe. "Today, the atrocious Gaddafi's brigades continued to bomb Sebha city viciously," said Mr Jibril, who is considered as prime minister of the interim rebel government, the National Transitional Council (NTC). "In the next stage, we must extend a helping hand and support to all the cities that have not yet risen, so as to rise and to join the procession of glory." Members of the NTC, which has so far been based in the eastern city of Benghazi, said they planned to fly to Tripoli on Wednesday to start work on forming a new government. Rebel representatives also prepared for high-level talks in Qatar on Wednesday with envoys of the US, UK, France, Turkey and the United Arab Emirates to discuss how to move ahead in the post-Gaddafi Libya. Meanwhile, the US state department said the US would seek to release between $1bn and $1.5bn (£600m and £900m) in frozen Libyan funds in the coming days, and hand the money to the NTC. The rebels swept into Tripoli at the weekend, but after a swift advance they met stiff resistance in a number of areas on Monday. The uprising against Col Gaddafi's 41-year rule began in February. The rebels held the east of the country and pockets of the west, before making their push towards the capital at the weekend. Nato air strikes have been targeting Col Gaddafi's forces, acting on a UN mandate to protect civilians.