Forces loyal to Libyan leader Moammar Gadhafi bombarded rebel positions in the Western Mountains region Wednesday, after rebels made advances toward the capital, Tripoli.

Rebels say Libyan forces fired Grad rockets at towns in the region, but they have not confirmed casualties from these attacks.

Rebels have made advances from the port city of Misrata toward Zlitan, about 135 kilometers east of Tripoli. Fighting lulled Wednesday as rebels held their positions.

The Associated Press reports that rebels say NATO has instructed them to stay away ahead of expected bombing in nearby Dafniya.

Meanwhile, the chief of NATO will discuss the alliance's operation in Libya with British leaders, after NATO resumed airstrikes on several targets in the Libyan capital hours earlier.

NATO Secretary General Anders Fogh Rasmussen is meeting with British Prime Minister David Cameron and Foreign Secretary William Hague in London.

Earlier this week, the head of Britain's Royal Navy warned that his British fleet might not be able to sustain the scale of its operations off the Libyan coast in the long term without cutbacks elsewhere.

NATO airstrikes rocked Tripoli, late Tuesday after a brief layoff. Witnesses say they heard loud explosions and saw plumes of smoke over the city center. Libyan state media say the bombings hit civilian sites, and there were reports of casualties.

NATO has been carrying out airstrikes on command centers and forces loyal to the Libyan leader since March.

In Tunisia, the official news agency TAP says 27 Libyan soldiers arrived in country's port of Ketf Tuesday after fleeing fighting. It is unclear from the report whether the soldiers have defected.