Libyan rebels say they have seized control of the western town of Zlitan, following intense battles with forces loyal to Libyan leader Moammar Gadhafi.

Rebels said Friday that they pushed into the center of the town, which is about 150 kilometers from Tripoli. The claim could not be independently verified. They also said at least 30 fighters were killed in clashes between the two sides.

The rebels – with NATO assistance – have been advancing slowly toward the capital, Tripoli.

The opposition fighters engaged in a second battle with pro-Gadhafi forces Friday in Zawiya, a town 50 kilometers west of Tripoli. The rebels said they seized control of an oil refinery at Zawiya on Thursday, and now control the nearby town of Sabratha.

Earlier, a series of explosions rocked Tripoli. Bombs fell near Libyan leader Moammar Gadhafi's main compound and several other areas of the city.

Libyan government spokesman Moussa Ibrahim condemned NATO, which has been helping the rebels with a campaign of airstrikes. Ibrahim's brother reportedly was killed by a NATO airstrike on Zawiya on Thursday.

NATO warplanes began combat missions over Libya in March, supporting the rebels fighting to put an end to Mr. Gadhafi's 42-year rule.

In a separate development, rebels Friday said former Libyan prime minister Abdessalam Jalloud has defected.

Jalloud helped Mr. Gadhafi stage the 1969 coup that propelled him to power and transformed Libya from a monarchy to a republic. He was Mr. Gadhafi's most trusted deputy for two decades before falling put of favor in the 1990s.

Meanwhile, the International Organization for Migration says it has launched an effort to evacuate “large numbers” of foreigners from Tripoli, because foreign nationals in the capital are becoming “increasingly vulnerable” and now want to leave Libya.