A Libyan military convoy with Muammar Gaddafi rumoured aboard has crossed into Niger, a military source said, as new regime fighters were poised to strike at the toppled strongman's last bastions.

Gaddafi's spokesman, Moussa Ibrahim, insisted the fugitive dictator is in top health and planning his country's defence, and that he and his sons are  ready to fight to the death, though he gave no clue of their whereabouts.

"I saw an exceptionally large and rare convoy of several dozen vehicles enter Agadez from Arlit... and go towards Niamey" late yesterday, the Niger military source said, referring to the northern Niger city of Agadez.

"There are persistent rumours that Gaddafi or one of his sons are travelling in the convoy," the source added.

A journalist from a private radio station in Agadez said he saw "a convoy of several dozen vehicles crossing the city and heading towards Niamey", the Niger capital.

Another Nigerien government source earlier said prominent regime officials had fled across the border on Sunday. They includedGaddafi 's internal security chief Mansour Daw, who was earlier reported to be in the loyalist stronghold Bani Walid with at least two of the fallen strongman's sons.

Anti-Gaddafi fighters said they are readfy to strike at Bani Walid, an oasis town southeast of Tripoli, at the slightest provocation.

Kamal Hodeisa, a Libyan defence ministry official, told AFP in Tripoli that anti-Gaddafi fighters would "move if there is an act of aggression by Gaddafi's forces against our rebels inside Bani Walid or if they attack civilians.

"There is debate among rebels whether to go forward or to stay but I think in the end they will respect the deadline," he said, referring to a truce until September 10 to try to negotiate the surrender of the last Gaddafi strongholds.

Abdullah Kenshil, the chief negotiator for Libya's new government, said civilians were being held hostage in the centre of the town, in administrative buildings and in five or six nearby villages.

"Gaddafi's soldiers have also closed the gates of the town and are not letting families leave," he said. "That worries us, we don't want to kill civilians in the attack."

Negotiations for the surrender of Bani Walid, southeast of Tripoli, broke down late Sunday but there was little movement on that front on Monday despite concerns that local families could be held as human shields.

Operational commander Abdulrazzak Naduri told journalists at Shishan, north of Bani Walid, that the National Transitional Council (NTC) does not "want any more bloodshed."

Gaddafi spokesman Ibrahim insisted however that the toppled leader was busy planning to re-take Libya.

Gaddafi is "in excellent health and planning and organising Libya's defence," Ibrahim told Syria's Arrai television channel on Monday.

"We are still powerful," he said, adding that the sons of the fugitive dictator "had assumed their role in the defence of and sacrifice for" their country. He however did not name them.

Pledging "a fight to the death or until victory," Ibrahim, who is thought to be in Bani Walid, said: "We will fight and resist for Libya and for all Arabs."

Branding the new rulers "NATO agents," he accused them of "commiting crimes, above all rape, murder and looting."

He said: "Libya will never fall and the worthy tribes are defending and will continue to defend each of the free town and recapture those that have been raped."

Local officials said most senior figures had fled Bani Walid with Gaddafi's most prominent son, Seif al-Islam, who according to Naduri left a few days before for Sabha, further south, that is still in the hands of regime loyalists.

Two other sons of Gaddafi, Saadi and Mutassim, were also reported to be in Bani Walid and it is suspected that the strongman himself crossed through the oasis town although it is unclear when.

No clashes were reported yesterday in Gaddafi's hometown of Sirte or the southern oases of Sabha and Al-Jufra.

China meanwhile denied reports of offering Gaddafi arms at the fag end of his regime. In Beijing, the foreign ministry acknowledged Libyan officials had visited in July for talks with "interested companies" but insisted no arms contracts had been signed nor any direct or indirect exports made.

"Chinese companies did not sign arms sales contracts and they did not export military products to Libya," spokeswoman Jiang Yu told journalists, adding her country "does not allow any actions that contravene UN resolutions."

Citing secret documents it had obtained, The Globe and Mail reported that state-controlled Chinese arms companies were ready to sell weapons and ammunition worth at least $200 million to Gaddafi in late July.

Britain yesterday re-established its diplomatic mission in Tripoli.

The UN Security Council is on Friday to discuss the launch of a wide-ranging mission to Libya to help tackle police reform, justice and election preparations, a UN diplomat told AFP on Monday.