The UK and France are drafting a UN resolution for an air exclusion zone and the issue is due to be debated by Nato defence ministers on Thursday, the idea already backed by Gulf Arab states. However, the international community is divided over the issue.
The debate comes as forces loyal to Col Gaddafi have launched counter-strikes against rebels, checking their recent advances.
In another development, unconfirmed reports said Col Gaddafi had sent a message to the rebels, offering to step down on condition he and his family were allowed to leave Libya safely with their wealth intact.
The rebel leadership in Benghazi – which calls itself the Transitional National Council – is said to have rejected the offer.
The prospect of a no-fly zone gathered pace after Gulf states supported the idea and also called for an urgent meeting of the Arab League. They have condemned the use of violence against civilians by Libyan government forces.
UK Foreign Secretary William Hague said Britain was working “with partners on a contingency basis on elements of a resolution on a no-fly zone”.
But he spelled out conditions attached to any such move.
Arab and African support would be crucial, he said, and there would need to be a clear trigger – most likely a sharp worsening of conditions for civilians.
Nato Secretary-General Anders Fogh Rasmussen also stressed the need for UN authorisation for any no-fly zone, adding: “I can’t imagine the international community and the United Nations would stand idly by if Gaddafi and his regime continue to attack their own people.
“We have asked our military to conduct all necessary planning so that we stand ready at short notice.”