Libyan fighters outside Bani Walid, a key city still controlled by supporters of toppled leader Muammar Gaddafi, have told Al Jazeera that efforts to negotiate a peaceful handover have ended.
An official for the National Transitional Council (NTC) said fighters were preparing to take the town by force after talks ended on Sunday.
"We are ready from three fronts: north and east and west," Mahmoud Abdul Aziz, a political analyst and one of those on the negotiation team, told Al Jazeera.
"Their time is over," he said, referring to Gaddafi loyalists in the town who had refused to give up their arms. "The push is going to happen in the next 24 hours."
Al Jazeera's Andrew Simmons reporting from As Saddadah in Libya said that there are unconfirmed reports of fighting within Bani Walid.
"This could be that that there are sleeper groups in that town [of Bani Walid] who are very much supporting the revolution and have started to rise in some parts of the town."
Al Jazeera's Sue Turton said that NTC fighters outside of Bani Walid have estimated Gaddafi troops remaining in Bani Walid number less than 100.
"This is aside from the Gaddafi loyalists who we've heard have come out, who are manning checkpoints... civilians who have weapons," she said. "But actual Gaddafi troops - they're saying no more than 100."
Some NTC fighters, who established a frontline about 30km from Bani Walid, suggested on Saturday that the town could be attacked within hours, and Al Jazeera's James Bays said on Sunday morning: "[NTC] forces are now surrounding Bani Walid and threatening to go in."
Bani Walid has been speculated to be a possible refuge for toppled Libyan leader Muammar Gaddafi and other members of his family.
Al Jazeera's Anita McNaught reports on divisions within Libya's Warfalla tribe.
Abdulrazzak Naduri, an NTC military commander in nearby Tarhuna, told the Reuters news agency that one of Gaddafi son's, Saadi, was in the town while another, Saif al-Islam, had recently fled.
Asked if Gaddafi was in the town, as claimed by NTC military commanders, Ali Tarhouni, the NTC's oil minister said: "As for Gaddafi himself... we know where he is."
'Allegiance to the leader'
The city, along with Sirte on the Mediterranean coast and Sabha deep in the Sahara desert, are the main pockets not under the control of NTC forces.
"What the NTC are hoping for Bani Walid, if they manage to get a settlement there, [is] that it will be the model for the other two [cities]," said our correspondent.
Gaddafi's spokesperson dismissed suggestions that Bani Walid was about to surrender and insisted that tribal leaders there were still loyal to the deposed leader.
"Bani Walid is a major city hosting one of the biggest tribes in Libya who have declared their allegiance to the leader and they refused all approaches for negotiation with the Transitional Council," Moussa Ibrahim told Reuters in a telephone interview.
Asked about Gaddafi's whereabouts, Ibrahim said the toppled leader was "in a safe place surrounded by many people who are prepared to protect him".
UN special envoy in Tripoli
A special envoy for Ban Ki-moon, the UN secretary general, arrived in Tripoli on Saturday to deliver a message that the world body was ready to assist in re-establishing security after the nearly seven-month uprising that toppled Gaddafi.
Ian Martin, the UN special adviser, told Reuters news agency on Sunday that Libya's election process needs to begin soon and the proliferation of weapons is a "major concern".
"I am here now to discuss with the National Transitional Council how the United Nations can be most helpful in the future," Ian Martin told reporters on arrival.
Martin arrived amid questions about the UN's future role in the country, particularly about whether a peacekeeping mission will be necessary.
"I think the future leaders of Libya face a very big challenge, they have already shown the ways in which they are ready to tackle that challenge and it will be the commitment of the United Nations to assist them in any way they ask."