Libyan rebels abandoned another key town today under heavy shelling from advancing government forces, as international backing grew only slowly for a no-fly zone over the country. Dozens of rebels were seen leaving the coastal town of Brega and heading for Ajdabiya, 80 kilometres away on the road to the main rebel cities of Benghazi and Tobruk. Rebel sources said forces loyal to strongman Moamer Kadhafi were approaching from the west, and Libyan state television, quoting an unspecified military source, later declared Brega purged of the armed gangs. In Benghazi, 240 kilometres east of Brega, all mobile telephone services were suddenly cut today for an unknown reason. It was not immediately clear if other rebel-held areas were also affected. Rebel morale had been boosted yesterday by an Arab League decision to support a no-fly zone over Libya and to make contact with the insurgents' provisional national council in Benghazi.But apart from defectors from Kadhafi's army, the rebels have no military experience and are virtually powerless against air attack. Declaring Kadhafi had lost all legitimacy, Arab foreign ministers urged the UN Security Council to assume its responsibilities in the face of the deteriorating situation in Libya and take the necessary measures to impose an air exclusion zone for Libyan warplanes. The United States welcomed the decision, which strengthens the international pressure on Kadhafi and support for the Libyan people, White House spokesman Jay Carney said in a statement.