Chad government forces fought desert battles Friday against rebels who were stepping up an offensive against President Idriss Deby, with more than 150 reported dead in two days of conflict. The fighting, centred on the eastern town of Am-Dam, has heightened concerns among UN agencies and aid groups caring for about 450,000 refugees from Sudan and the Central African Republic. The UN Security Council was to meet Friday to discuss the conflict. France, which has troops in Chad, was anxiously watching events. The European Union and African Union both condemned the rebel offensive. Chad has bombed the rebels from planes and helicopters since they crossed the Sudanese border Monday. The government accuses Sudan of backing the Union of Resistance Forces (UFR) rebels, who have vowed to take the capital Ndjamena.