Tripoli was rocked by a series of airstrikes by NATO forces in the early hours of the morning Sunday.
Libyan television reported that the "NATO crusader forces" had hit civilian and military targets in the eastern suburb of Tajoura.
Just after midnight Sunday, a series of dull rumbles and flashes could be seen to the east of Tripoli, illuminating huge plumes of smoke and accompanied by the sporadic tracers of antiaircraft fire.
The distant rumbling blasts continued for at least an hour, suggesting some kind of facility with explosive materials had been hit.
Aircraft could be heard soaring through the night sky, which was illuminated by a nearly full moon.
NATO fighters have been carrying out airstrikes against Libyan military targets as part of a U.N.-mandated operation to protect civilians.
The blasts come after three days of defiant speeches by Libyan leader Moammar Gadhafi.
Gadhafi said Saturday afternoon that his country will never surrender in the face of assaults by rebels and a NATO air campaign.
In an audio address directed at the city of Zawiya where thousands demonstrated their support, Gadhafi promised that Libya would keep fighting.
"After we gave our children as martyrs, we can't backtrack, or surrender or give up or move an inch," he said, his voice booming over loudspeakers in the center of town. "Rest assured in your tombs, our martyrs, we will not betray you ever."
The speech was the third in as many days, each addressing inhabitants of a town under his control while thousands chanted their support for the country's leader of the past 41 years.
In his speech, also broadcast on national television, Gadhafi said the NATO airstrikes on Libya must stop to save civilian lives.
The rally was staged in the center of Zawiya, a city once under rebel control in the early weeks of the revolt against Gadhafi's rule and only taken back after a brutal battle.
The center of the city still bore scars of the fighting, with burned out and shattered buildings overlooking the cheering crowds swathed in green, Libya's national color.
"Here is Zawiya. Where are the ... traitors and the agents that you depended on? Where are those you bought with your money, you brainwashed?" he asked, addressing NATO.
"Zawiya can't be ruled by agents, nonbelievers and traitors who are seeking help from the cross," he added.
The speeches and rallies come after Libya's main opposition group was recognized by more than 30 nations, including the U.S., as Libya's legitimate government.
Friday's decision potentially frees up billions of dollars in cash that the rebels urgently need.
Libya's civil war has fallen into a stalemate since the mass uprising seeking to oust ruler Gadhafi broke out in mid-February. Rebels have set up an interim administration in the eastern city of Benghazi and seized control of the port city of Misrata and much of the western Nafusa mountain range.
Gadhafi controls the rest of Libya from his stronghold in the capital Tripoli.
Rebel forces _ mostly volunteers armed with captured weapons _ have failed to make significant advances recently, even with NATO bombing Gadhafi's troops under a U.N. mandate to protect civilians.
On Saturday 10 rebels were killed in their latest advance on the strategic oil town of Brega. Rebel fighters said they were sweeping the outskirts for land mines so they could move in.
Rebels have been trying to take the town with its large gas and oil storage facilities for weeks.
Associated Press Writer Sarah El Deeb in Cairo contributed reporting.