The BBC's Allan Little in Tripoli says the sky above the capital lit up with anti-aircraft fire again on Monday night, repeatedly in short bursts which lasted several minutes on each occasion.
Our correspondent heard one loud explosion nearby and several distant rumbles much further afield. The AFP news agency reported that a blast was heard near Col Gaddafi's sprawling Bab al-Aziziya compound.
Libyan state television reported that the capital was "currently under crusader enemy aerial bombardment" and that several sites had been attacked.
For more: BBC News - Libya: Tripoli gunfire and explosions for third night