The green flags of Gaddafi supporters are being torn down. The whereabouts of the estimated 65,000 pro-Gaddafi soliders defending Tripoli are unknown.
In most parts of the city now residents are setting up road blocks to prevent security forces moving against the rebels.
There are reports that Colonel Gaddafi’s son, Saif al-Islam has been captured by the rebels.
National Transitional Council (NTC) chairman Mustafa Mohammed Abdul Jalil told al-Jazeera TV he was “being kept in a secure place under close guard until he is handed over to the judiciary”.
Libyan Information Minister Moussa Ibrahim said fighting in Tripoli since noon on Sunday had left 1,300 people dead and 5,000 wounded, and added that hospitals could not cope with the casualties.
Throughout the night and much of the day there has been the sound of gunfire, small arms and heavy weapons and explosions. Both sides fighting in what may be the final battle of this six-month-long conflict.
A government source here believes that local tribes are preparing to protect their own. There is a fear among some in government circles that if the rebels are allowed to reach Tripoli, the city could be on the verge of all-out tribal warfare.
Rebel fighter Mohammed al-Zawi told AP he had been in a convoy of more than 10 lorries that entered the district of Ghot Shaal on the western edge of the city.
They advanced as far as the district of Girgash, about 2km from Green Square, the traditional rallying-point for Gaddafi loyalists over the years, when they came under sniper fire from a rooftop.
“They will enter Green Square tonight, God willing,” he added.
The information minister insisted the government was “very resilient”. “We have thousands and thousands of fighters,” he said. That may be true but are they willing to die for a lost cause?