Sirte: Hundreds of revolutionary forces have pushed into Muammar Gaddafi's hometown of Sirte in the first significant assault in about a week.

Explosions rocked the city and plumes of smoke rose into the sky Saturday as revolutionary fighters fired rockets and heavy artillery from outside and Gaddafi's forces returned fire.

The fighters have occupied a key roundabout called Zafaran west of the downtown area. They say their goal is to occupy two neighbourhoods on the western side of the city.

The two sides have been locked in a stand-off since revolutionaries tried to advance on the city a week ago but were repelled by fierce resistance.

Sirte is one of three Gaddafi strongholds that refused to surrender after revolutionary forces seized control of Tripoli.

Daughter's message

Meanwhile, Gaddafi's firebrand daughter has said in an audio recording that her father is in high spirits and fighting alongside his supporters.

In her first public remarks since the fall of Tripoli a month ago, Aisha Gaddafi accused the country's new leaders of being traitors, noting that some of them were members of Gaddafi's regime before defecting in the civil war.

"Those who have betrayed the pledge they offered [to Gaddafi], how come they won't betray you?" she said in a pre-recorded message broadcast on Syrian TV.