Libya’s government has dismissed as “mad” the conditional ceasefire offer made by the rebel administration.
Spokesman Moussa Ibrahim said troops loyal to Col Muammar Gaddafi would never withdraw from the rebel-held cities they were besieging.
He also condemned recent coalition air strikes as “a crime against humanity” and said there had been civilian casualties in one attack on Thursday.
Nato is investigating a report that seven civilians were killed near Brega.
The account, from a doctor in Adjabiya, could not be independently verified.
‘Crime against humanity’
On Friday, the head of the rebel Transitional National Council, Abdul Jalil Ibrahim, discussed how a truce might come about after meeting UN special envoy Abdelilah al-Khatib in the eastern city of Benghazi.
“We have no objection to a ceasefire but on condition that Libyans in western cities have full freedom in expressing their views and also that the forces that are besieging the cities withdraw,” he told reporters.
“Our main demand is the departure of Muammar Gaddafi and his sons from Libya. This is a demand we will not go back on.”
Mr Abdul Jalil, who quit as justice minister in protest at the use of violence against demonstrators, also said he believed the coalition should begin arming the rebels despite the UN arms embargo on Libya.
“We think that if the international community wants to protect civilians according to the international resolutions, they should take the appropriate measures, which include giving the go ahead to arm the rebels,” he added.
Moussa Ibrahim dismissed the offer of conditional ceasefire, describing the rebels as “tribal, violent, with no unified leadership, al-Qaeda links.”
“The rebels never offered peace. They don’t offer peace. They are making impossible demands.”
“If this is not mad, I don’t know what is,” he added. “We will not leave our cities. We are the government, not them.”
Mr Ibrahim also said six civilians had been killed by an “immoral” air strike in the eastern village of Zawia el Argobe, 15km (9 miles) from Brega.
“Some mad and criminal prime ministers and presidents of Europe are leading a crusade against an Arab Muslim nation,” he told reporters in Tripoli. “Sounds familiar? It’s a crime against humanity.”