NORTH OF BANI WALID, Libya - Columns of anti-Gadhafi forces sped towards Bani Walid on Friday after their position came under attack and one of their number said they were planning to take the town, one of the last bastions of support for the ousted Libyan leader.

"We have received orders from our commanders and we are going into Bani Walid today from different locations," anti-Gadhafi fighter Mohammed Jwaida told Reuters at a factory 20 km (15 miles) north of the city, where the rebels were dug in.

"We were planning to do this today anyway but Gadhafi forces launched this attack to prevent our advance. They thought we would run away, they are cowards," he said.

"We have about a thousand fighters here today," he said, adding that they would not use heavy artillery because "we do not want to harm civilians".

Earlier, rockets fired by Gadhafi forces in Bani Walid had hit the factory, which is also used as a field hospital. Doctors there said no one had been wounded or killed in the attack. An exchange of heavy machinegun fire followed and large numbers of anti-Gadhafi forces set off to chase the attackers.

"Gadhafi forces fired four or five rockets. We are reinforcing our position and going forward," said anti-Gadhafi fighter Mohamed Al Lawaj.

The desert town has been under siege for two weeks, with die-hard Gadhafi loyalists dug into its steep valleys and hills resisting advancing interim government forces