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
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.