Explosions were reportedly heard in eastern Tripoli for almost an hour Wednesday morning as jets flew overhead.
Nato said that since the alliance took over military operations on 31 March to protect civilians from pro-Kadhafi forces, jets have conducted more than 2,300 strike missions.
Officials insisted however that the raids were not aimed at killing Kadhafi.
"All Nato targets are military targets, which means that the targets we've been hitting are command and control bunkers," Brigadier General Claudio Gabellini told reporters on Tuesday.
But asked whether Kadhafi was still alive, the Italian Nato general said: "We don't have any evidence. We don't know what Kadhafi is doing right now".
Heavy bombardment had also been reported in Tripoli early on Tuesday morning.
Kadhafi survived a similar Nato bombing on 1 May in Tripoli, which killed his second-youngest son, Seif al-Arab, and three of his grandchildren.
Meanwhile, rebel forces said they had driven Kadhafi's forces back from around the western port of Misrata, which has been under loyalist siege for some two months, and were poised to make another thrust.
EU foreign policy chief Catherine Ashton said Wednesday that the EU plans to open an office in the Libyan city of Benghazi to improve the flow of aid for the authorities there.
The office will help support civil society and the Interim Transitional National Council opposed to Kadhafi.