Fresh fighting erupted on Thursday in the centre of Tripoli near Muammar Gaddafi's Bab al-Azizya compound, captured by rebel fighters the previous day.
Thick smoke hung over the complex, where rebels and Gaddafi's forces were fighting early afternoon with light weapons, heavy machine guns, rocket propelled grenades (RPGs) and mortars, an AFP reporter said.
Fighting also spread to the nearby Abu Slim area, where rebels were seen to be retreating.
Rebel commanders said they were determined to push the loyalist troops out of the area, which houses the Rixos hotel where around 30 foreign journalists remain trapped.
Many streets were deserted in the city centre, where commanders said dozens of pro-Gaddafi snipers have taken up positions.
"There are snipers above and around the perimeter of Bab al-Azizya; there are dozens of them but we don't know where they are," said the chief of a rebel group, Nuri Mohammed.
Fighting flared sporadically through the night following yesterday's storming of the compound, the symbolic seat of Gaddafi's power.
Two powerful blasts thought to be caused by an air attack rocked the capital early today as a NATO warplane flew overhead.