Libya's new rulers had set today's deadline for Gaddafi loyalists in Bani Walid to surrender or face an offensive but decided to attack yesterday evening after Gaddafi forces fired volleys of rockets at the fighters' positions around the town.
Abdullah Kenshil, the former rebels' chief negotiator, said the former rebels were fighting gunmen positioned in houses in the town and the hills that overlooked it.
Anti-Gaddafi forces were moving in from the east and south, and the fighters deepest inside Bani Walid were clashing with Gaddafi's men about 2 kilometres from the centre of the town, Kenshil said.
Revolutionary forces also battled loyalists to the east of the Gaddafi stronghold of Sirte on the Mediterranean coast, but were forced to pull back after taking heavy casualties in close-quarters fighting, a spokesman said.
Before the reported yesterday evening assault on Bani Walid, Gaddafi holdouts in the city fired mortars and rockets toward the fighters' position in a desert dotted with green shrubs and white rocks, killing at least one and wounding several.
Loud explosions were heard about 10 kilometres from the front line, followed by plumes of black smoke in the already hazy air. NATO planes circled above.
NATO says it is acting under a UN mandate to guarantee the safety of Libya's civilian population. Its bombing campaign has been crucial to the advance of Gaddafi's military opponents.
Daw Salaheen, the chief commander for the anti-Gaddafi forces' operation at Bani Walid, said his fighters responded with their own rocket fire, and advanced on the town.
"They are inside the city. They are fighting with snipers," Kenshil said. "They forced this on us and it was in self-defence." He said three Gaddafi loyalists had been wounded and three killed, while the former rebels had one dead and four wounded.
He said the former rebels had taken seven prisoners. Kenshil said the former rebels believed that there were about 600 Gaddafi supporters in and around Bani Walid.
"Snipers are scattered over the hills and the rebels want to chase them," he said.
"There is hand-to-hand combat. The population is afraid so we have to go and protect civilians."