Tribes loyal to Libyan leader Muammar Gaddafi have given the army an ultimatum to drive rebels out of the besieged city of Misrata or let them do the job, a senior official says.
Deputy Foreign Minister Khaled Kaim said the army had tried to keep civilian casualties low but the tribes would not show the same restraint.
He said the army would remain in place.
Col Gaddafi’s forces have been pounding Misrata – the main rebel-held area in western Libya – for weeks.
Rights groups say more than 1,000 people there have died.