A series of thunderous booms rumbled in quick succession shortly before 5 a.m., rattling windows in the heart of the city. A column of smoke could be seen rising from the vicinity of the Libyan leader's Bab al-Aziziya compound as sirens from emergency vehicles blared through the streets.
It was not clear what was hit, and there was no word on casualties. Government officials did not immediately comment on the strike.
NATO warplanes have repeatedly targeted the area in and around the compound. Rallies in support of the leader and his more than four-decade rule are held there nightly.
The alliance launched its air campaign nearly three months ago under a United Nations resolution to protect civilians. What started as a peaceful uprising inside the country against Gaddafi has become a civil war, with poorly equipped and trained rebel fighters taking control of the eastern third of Libya and pockets of the west.
The fighting had reached a stalemate until last week when NATO launched the heaviest bombardment of Gaddafi forces since the alliance took control of the skies over Libya. NATO has been pounding Gaddafi's military and government positions with increasing vigor and the rebels are again on the move.
Britain's prime minister said that time is running out for Gaddafi's forces, even as some senior military leaders within NATO have voiced concerns that the mission is straining the alliance's resources.