A US warplane has crashed in eastern Libya following an apparent mechanical failure, the US military says.
US spokesman Kenneth Fidler told the BBC there was no indication the F-15E Eagle had been brought down by hostile fire.
Both crew members ejected and are now safe, the military says.
The plane reportedly went down near the rebel stronghold of Benghazi. It follows a third night of allied air strikes against Col Gaddafi's forces.
A US-led coalition has been in action over Libya since Saturday, enforcing a UN resolution to protect civilians from government troops.
The BBC's Allan Little in Tripoli says the sky above the capital lit up with anti-aircraft fire again on Monday night.
Our correspondent heard one loud explosion nearby and several distant rumbles much further afield. AFP news agency reported that a blast was heard near Col Gaddafi's Bab al-Aziziya compound.
Libyan state television reported that the capital was "under crusader enemy aerial bombardment" and that several sites had been attacked.
The Libyan authorities said a naval base at Bussetta, about 10km (six miles) east of Tripoli, and a fishing village had also been hit.
Libyan government spokesman Moussa Ibrahim said Monday's air and missile strikes had caused "numerous" civilian casualties, especially at the "civilian airport" in Sirte.
US Defence Secretary Robert Gates said on Tuesday that coalition forces were "going to great lengths to avoid civilian casualties".
Mr Gates, after talks in Moscow with his Russian counterpart Anatoly Serdyukov, added: "I also told him that I thought the significant military fighting that has been going on should recede in the next few days."
Russia, which abstained in last week's UN Security Council vote on the resolution authorising force in Libya, has since criticised the air strikes.
Fighting between Col Gaddafi's forces and the rebels has continued, despite the declaration of a ceasefire by the government.
A doctor in Misrata - the last rebel-held city in western Libya - told the BBC on Tuesday that residents had suffered another night of shelling by government forces.
He reported 22 deaths overnight and said more than 100 people had been injured.
There are also reports of continued fighting in Zintan, near the Tunisian border.
On Monday US President Barack Obama said the US would soon cede control of operations in Libya - "in a matter of days and not in a matter of weeks".
But divisions have emerged over a possible transfer of command to Nato.
Mr Gates has said the mission could be under French-British or Nato control.
But some allies - including France - are opposed to Nato taking over.
Norway said its jets would not take part in the action as long as it was unclear who was in overall command.
Nato officials say they do not expect any decision for several days on whether the alliance should play a command-and-control role in military operations around Libya.
Meanwhile rebel leaders based in eastern Libya have had talks with United Nations officials on the humanitarian situation there.
The BBC's Kevin Connolly in Tobruk, where the talks were held, says that although food is being imported in the region from Egypt, it is not clear how viable the local economy will be if it remains cut off from the rest of Libya.