There are reports of dozens of deaths in the western Libyan town of Zawiyah where Colonel Gaddafi’s forces have been stepping up efforts to regain control.
An amateur video said to have been filmed in the town shows chaotic scenes, with apparent casualties lying on the ground while others are dragged away.
According to one report, a resident claims the local hospital was full of casualties. Other witnesses are quoted as saying that African mercenaries fired into the crowd, and that up to 50 people were killed.
The reports cannot be immediately verified.
A spokesman for rebel forces has said their senior commander in the area was killed.
The rebellion in Zawiyah has been an embarrassment to the government. It is the closest rebel-held territory to Tripoli and also the site of an oil refinery.
In one part of the capital, shooting rang out as forces loyal to Muammar Gaddafi broke up a crowd of demonstrators.
They had reportedly started shouting anti-Gaddafi slogans in the Tajoura district after Friday prayers.
Suddenly security forces and government supporters arrived. Tear gas and baton rounds were fired.
The protest is seen as a sign that there is perhaps significant opposition to the regime in and around Tripoli as well as other parts of the country.