NORTH GATE OF BANI WALID, Libya (Reuters) - Hundreds of Libyans fled a desert town held by Muammar Gaddafi's forces on Tuesday, complaining of hardship and intimidation, as fighters backed by the country's new rulers warned of a full onslaught in the coming days.
Forces of the new ruling National Transitional Council (NTC) that overran Tripoli on August 23 have met unexpectedly stout resistance in five days of fighting for the town of Bani Walid 180 km (110 miles) southeast of the capital.
Along with Gaddafi's hometown Sirte on the central Mediterranean coast and Sabha in the remote southern desert, Bani Walid counts among the last strongholds of old regime fighters and their resistance has impeded NTC efforts to normalise life in the oil-rich North African state.
Residents fleeing the town have reported days of intense firefights, and NATO warplanes were backing up NTC fighters with air strikes on pro-Gaddafi rocket positions.
Families trapped there for weeks started to slip out after Gaddafi forces abandoned some checkpoints on the outskirts, and scores of cars packed with civilians streamed out of the area on Monday and Tuesday.
NTC field commanders said people in Bani Walid, dominated by a tribe, the Warfalla, that was a pillar of Gaddafi's rule, had been told via broadcast radio messages they had two days to leave town before it came under full-blown attack.
"I think only 10 percent of the people are Gaddafi supporters. They are fanatics. And the rest are waiting to be liberated. We have given them two more days to leave the city," NTC fighter Abumuslim Abdu told Reuters.
But 25-year-old resident Abdulbaset Mohamed Mohamed painted a slightly different picture of Gaddafi support as he drove towards Tripoli dressed in a football kit and sporting freshly slicked-back hair.
"It's too dangerous to go outside. Militia men are hiding around the city and (pro-Gaddafi) green flags are everywhere," he said.
The United Nations said it was worried about the plight of civilians marooned inside besieged pro-Gaddafi towns.
"Our big concern right now is Sirte, where we are receiving reports that there's no water and no electricity," U.N. humanitarian chief Valerie Amos told Reuters in Dubai.
Some NTC combatants said they suspected local fighters of the Warfalla tribe, Libya's largest, were passing tips to Gaddafi forces in Bani Walid. "We believe there are traitors among them," said Mohammed el Gahdi, from the coastal city of Khoms.
But efforts to get Libya running again were also gathering pace, especially in its life-blood oil sector.
The Arabian Gulf Oil Company (Agoco) said on Tuesday that production from the eastern oilfield of Sarir had reached 160,000 barrels per day (bpd) and that it had begun to send crude oil to the export terminal of Tobruk.
NTC chairman Mustafa Abdel Jalil also made his first public speech in Tripoli late on Monday -- just hours after Gaddafi loyalists attacked the gate of an oil refinery.
Despite the assault, Abdel Jalil felt confident enough to address a crowd of about 10,000 people in the central Martyrs' Square and use the speech to call for restraint.
"We seek a state of law, prosperity and one where sharia (Islamic law) is the main source for legislation, and this requires many things and conditions," he said, adding that "extremist ideology" would not be tolerated.
Human rights group Amnesty International warned in a report on Tuesday that the security vacuum risked plunging Libya into a bloody vortex of attacks and reprisals.
"We need to open the courts to anyone who harmed the Libyan people in any way. The judicial system will decide," Jalil said in Tripoli, urging NTC fighters to respect that principle.
Jalil has said that, along with taking control of pro-Gaddafi enclaves, capturing or killing the fugitive leader is a priority and only then could Libya be declared "liberated."
NTC sources said on Tuesday that Abdel Hafid Zlitni, a former Central Bank governor and finance minister, was captured in Zawiyah, 50 km west of Tripoli.
They also said Mohammed Zwei, parliament speaker and former ambassador to Britain had been captured in the past week. Senior military officer Mustapha Kharroubi was also now in NTC custody, witnesses said.
Kharroubi is a veteran Gaddafi official and one of the few remaining officers who participated in Gaddafi's 1969 coup. It is believed he handed himself over to NTC officials late last month but this could not immediately be confirmed.
Gaddafi's entourage in Libya is dwindling. One of his sons, Saadi, arrived in neighbouring Niger on Sunday after crossing the southern Sahara desert frontier.
Two other sons and Gaddafi's only biological daughter have made their way out to Algeria. One son is reported to have died in the war and three others are still on the run.
The NTC has said it will send a delegation to Niger to seek the return of anyone wanted for crimes under Gaddafi's rule.
Additional reporting by William Maclean, Hisham el-Dani and Alexander Dziadosz in Tripoli, Sherine El Madany in Ras Lanuf, Emma Farge in Benghazi, Mark John and Bate Felix in Niamey, Barry Malone and Sylvia Westall in Tunis; Writing by Barry Malone; Editing by Mark Heinrich