At least seven loud blasts were heard in Tripoli early today as bombs fell in the vicinity of Muammar Gaddafi's main compound of Bab al-Aziziya.

Explosions were reported as bombs struck the ground, with Nato jets heard circling the sky above.

Residents in Tripoli also told reporters that at least three blasts were heard on the road leading to the airport in the capital.

Nato has been bombarding military targets in Libya since a no-fly zone was instituted in March.

That includes areas near and in Gaddafi's sprawling Bab al-Aziziya compound, the Libyan leader's main headquarters which also acts as a military barracks.

Just 30 miles to the west of the capital, opposition fighters in Libya's western mountains claimed control of the country's last functioning oil refinery yesterday, a blow to Gaddafi's regime in a week of rebel advances that could turn the tide of the six-month-old civil war.

The refinery is located in the strategic city of Zawiya, where rebels have made great strides in battles with government forces since their initial assault on Saturday.

A rebel victory in Zawiya could leave Gaddafi nearly cornered in his increasingly isolated stronghold in the capital, 30 miles to the east along the Mediterranean coast.

Rebel fighters are now closing in on the capital from the west and the south, while Nato controls the seas to the north. The opposition is in control of most of the eastern half of the country and has declared Benghazi, 620 miles east of Tripoli, as its de facto capital.

Families fleeing their homes to avoid a possible rebel assault on Tripoli described growing tensions and deteriorating living conditions in the capital.

Security forces have blanketed the city with checkpoints, gun battles are heard after nightfall and power outages last days.