Libyan interim government fighters have trained tanks on Sirte, the hometown of deposed leader Muammar Gaddafi.
Anti-Gaddafi forces are believed to be 2 kilometres from the centre of the desert town after NATO launched weekend air-strikes.
Sirte is key if the National Transitional Council is to establish credibility and begin the difficult job of uniting Libya’s tribes and regions after months of bloodshed and chaos.
Aid agencies also want the fighting to stop amid fears for the civilian population.
NTC forces seized a Gaddafi weapons dump hidden on a farm close to the colonel’s stronghold. Sirte, some 400 kilometres from Tripoli, is one of the last remaining bastions where Gaddafi claims support.
Local NTC commanders say it is only a matter of time before they take control of the town.