Fighters for Libya's new rulers began an assault to overrun one of the last bastions held by pro-Moamer Kadhafi forces, as secret files shed light on his fallen regime's links to US and British spy agencies.
"We are preparing to enter Bani Walid and we will fight," Mahmud Abdel Aziz, a local spokesman for the National Transitional Council told AFP at a checkpoint in Shishan, just dozens of kilometres (miles) north of Bani Walid.
A dozen vehicles, including pick-ups mounted with heavy machine guns, were seen heading further south towards Bani Walid while a commander, Ossama Ghazi, also set off on Saturday, saying: "There is fighting."
Abdel Aziz said he expected Bani Walid to "fall within hours."
"People there have asked for more time but our patience has worn out."
Earlier, the deputy chief of the military council of the town of Tarhuna, further north, said fighters for Libya's new leaders have given forces in Bani Walid until 0800 GMT Sunday to surrender.
Abdulrazzak Naduri said Kadhafi's son Saadi was still in Bani Walid, along with other regime cronies, while prominent son Seif al-Islam had fled the town.
"The revolutionaries have given an ultimatum to the tribal chiefs in Bani Walid," Naduri told AFP in Tarhuna, some 80 kilometres (50 miles) north of Bani Walid.
"Either they raise the white flag of surrender or the fighting begins."
The offensive appeared to be well underway even though NTC chairman Mustafa Abdel Jalil said in Benghazi that a truce declared until September 10 was still in force.
"We are in a position of strength to enter any city but we want to avoid any bloodshed, especially in sensitive areas such as tribal areas," he said, adding military deployments would continue during the ceasefire.
Naduri said Saadi Kadhafi, the toppled strongman's spokesman Mussa Ibrahim, and Mansur Dau, head of the revolutionary committees that propped up Kadhafi's regime, were still in Bani Walid.
But Seif al-Islam, the regime's most prominent face and vocal interlocutor, had fled two days ago, he said. "God alone knows which road he took," he added.
Meanwhile, Kadhafi regime intelligence files seen by AFP on Saturday appear to document deep cooperation between the CIA, MI6 and the former Libyan regime, including the shipping of terror suspects for regime interrogation.
The cache of documents, originally obtained by Human Rights Watch from a Libyan security archive, includes blunt details about the secret 2004 seizure from Malaysia of an Islamic militant, who by twist of fate now commands the revolutionary forces in Tripoli.
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The letters include an apparent CIA memo informing the Libyan authorities about the journey of "Abdullah al-Sadiq" and his pregnant wife from Kuala Lumpur to Bangkok, where the US would "take control" of the pair and hand them over to the regime.
Sadiq -- named as a member of the Libyan Islamic Fighting Group -- is said to be the nom de guerre of Abdel-Hakim Belhaj, who now leads the militia of Libya's new rulers in the capital Tripoli.
In another letter, a senior member of Britain's intelligence agency congratulates Libya's spymaster on the arrival of Sadiq.
The documents also show how the Central Intelligence Agency, under the administration of then US president George W. Bush, brought other terror suspects to Libya and suggested questions Libyan interrogators should ask them.
The cache also shows it was the office of former British prime minister Tony Blair that requested that a 2004 meeting with Kadhafi in Tripoli should take place in a Bedouin tent.
An unnamed US official quoted by the Wall Street Journal noted that, at the time, Libya was breaking diplomatic ice with the West.
The cache is also shows that a statement given by Kadhafi announcing his regime was giving up weapons of mass destruction in a bid to shed its pariah status was put together with the help of British officials.
British Foreign Secretary William Hague refused to be drawn Saturday on the reported files detailing the closeness of ties between London and Tripoli, insisting they related to the previous government.
"What we're focused on is getting the necessary help to Libya, more recognition for the National Transitional Council, getting the assets unfrozen so we avert any humanitarian problems in Libya," he told Britain's Sky News.
A Foreign Office spokeswoman told AFP: "It is the long-standing policy of the government not to comment on intelligence matters." In Washington, the State Department similarly declined to comment.
Meanwhile, The Sunday Times reported that Britain invited two of Kadhafi's sons, Khamis and Saadi, to the headquarters of the SAS special forces unit to watch "VIP demonstrations." But the Ministry of Defence said the visits did not go ahead.
"The article alleges that they were invited on two particular dates in 2006. We have checked and no such visits took place," a spokesman told AFP.
In the latest revelations from intelligence documents obtained by media and rights groups in Tripoli, the paper said Blair had also helped another of Kadhafi's sons, Seif al-Islam, with his doctoral thesis.
Elsewhere on Saturday, a special adviser for UN Secretary General Ban Ki-moon arrived in Tripoli, as the international body and Libya's new leaders stepped up efforts to bring order and democracy to the country.
Ian Martin landed at a military airbase in the capital, after Ban said the world body was ready to assist in re-establishing security following the nearly seven-month uprising that ousted Kadhafi.
And almost two weeks since anti-Kadhafi forces overran Tripoli, there were signs of life returning to normal in the capital.
There was still no firm word on the whereabouts of the toppled strongman after he defiantly threatened to lead a protracted insurgency in audio tapes aired by Arab media on Thursday.
The victors extended until next weekend an ultimatum for the surrender of remaining loyalists to give time for negotiations to bear fruit.