Heavy artillery fire rocked the Libyan town of Sirte Saturday as provisional government fighters battled former leader Moammar Gadhafi's loyalists.

National Transitional Council fighters pushed into the town's center earlier this week but have been facing stiff resistance from snipers and other pro-Gadhafi forces.

The provisional fighters are also trying to gain the upper hand in Bani Walid, a desert town that is among the few remaining strongholds for Mr. Gadhafi's supporters.

Meanwhile, NTC chairman Mustafa Abdel Jalil says an interim government will be announced in the coming week. He commented Saturday in Benghazi, where the NTC has been meeting to discuss the new government's formation.

Jalil said membership in the provisional government is a right guaranteed to all Libyans. He noted that two seats would be reserved for representatives from Sirte, the hometown of Mr. Gadhafi.

Earlier, an NTC spokesman said the government would include 22 ministers and a deputy prime minister.

Mr. Gadhafi's whereabouts remain unknown. On Friday, his daughter, Aisha Gadhafi, released an audio recording in which she says her father was in high spirits and fighting alongside his supporters.

The message was aired by Syria-based Arrai television. Aisha Gadhafi called the country's new leaders “traitors” because some of them had been part of the Gadhafi government.

Aisha, her mother and two brothers fled to Algeria in August as NTC fighters swept into Tripoli.