Forces of Libya's interim rebel council have met "ferocious" street-by-street resistance during their assault on the Qaddafi bastion of Bani Walid.

National Transitional Council forces, who toppled Qaddafi last month, said they were facing about 1,000 loyalist fighters in the Qaddafi stronghold of Bani Walid, far more than the 100 to 150 men they had expected, while discipline in their own ranks was slipping.

Last week international media outlets accurately reported the number of Qaddafi loyalists in Bani Walid.

Residents fleeing Bani Walid reported heavy fighting in the streets, while NATO warplanes could be heard overhead.

“There has been a ferocious resistance from them at Bani Walid. I don’t know how long it’s going to take [to capture it],” NTC spokesman Jalil al-Galal told Reuters Sunday.

The NTC says it will not declare Libya “liberated” until it has taken control of towns still in the hands of Qaddafi loyalists. It had given those towns a deadline of Saturday to surrender and its fighters have been battling since Friday inside Bani Walid, 150 kilometers southeast of the capital.

They said they were meeting tougher resistance than expected in Bani Walid, but were advancing toward Sirte, which sits on the main east-west coast road, effectively cutting Libya in two.

NTC troops said the front line was about 90 kilometers east of Sirte. Firing from tanks, howitzers and heavy machine guns could be heard above the roar of NATO warplanes overhead.

“Qaddafi forces were firing Grad rockets, but we managed to advance a little bit and we will enter Sirte very soon,” fighter Salah al-Shaery said.

The interim government has sent additional brigades to Bani Walid, but some fighters on the ground said the move had only worsened existing tribal sensitivities.

“Locals don’t listen to NTC commanders,” fighter Esam Herebish told AFP. “They do what they like. They want to be seen as the city’s liberators.”

Families trapped inside Bani Walid for weeks fled the besieged town Monday after Qaddafi forces abandoned some checkpoints on the edge of the city. Dozens of cars packed with civilians streamed out of the area.

Residents described scenes of intense street-to-street fighting, saying that Qaddafi forces were shelling residential areas to stop NTC fighters from advancing.

One man driving out of Bani Walid in a car packed with women and children said they were fleeing fierce fighting in the town.

“We are leaving because of the rockets. They are falling near civilian homes,” Ali Hussain said.

One NTC commander, Mohammad el-Fassi, said troops sent to reinforce the anti-Qaddafi onslaught from elsewhere in Libya had actually made advances more difficult.

“When we entered Bani Walid, Qaddafi forces started firing rockets in residential areas, targeting our fighters,” he said, adding that some had advanced into the town without orders to do so, contributing to their lack of progress on the front line.

“Our fighters are from all over Libya. There was little control over them yesterday. Today we will control them better,” he said, adding that five NTC fighters were killed and 14 wounded in Sunday’s clashes.

Fighters trying to take the town also said they suspected local fighters of the Warfalla tribe, Libya’s largest, of passing information to pro-Qaddafi forces inside Bani Walid.

“We believe there are traitors among them,” said Mohammed el Gahdi, a fighter from the coastal city of Khoms.

NTC military spokesman Ahmad Bani told reporters the plan for Bani Walid for now was to wait.