Rebel forces in Libya say they will accept a ceasefire - if Colonel Muammar Gaddafi pulls his forces out of cities under their control and allows peaceful protests.
But opposition leader Mustafa Abdul Jalil said they will not back down on their demand that Colonel Gaddafi must go.
Pro-Gaddafi forces are reportedly bombarding the town of Misrata which is held by the rebels and are getting close to Brega, which is now the front line.
Misrata is Libya's third biggest city 200km east of Tripoli. Brega is about 800km east of Tripoli.
The BBC reports the morale of rebel fighters has been boosted by a number of well-armed, apparently well-trained soldiers in full military uniform. It was not clear where they had come from.
Meanwhile, a senior aide to the Libyan regime has visited Britain in recent days for talks with officials.
Mohammed Ismail, who is an aide to Colonel Gaddafi's son, Saif al-Islam, was reportedly told that Colonel Gaddafi had to leave office.
The Foreign Office has refused to comment.
Colonel Gaddafi has been in powr for 41 years.