NAIROBI, KENYA -- At least 16 western relief agencies have received letters from the Sudanese government telling them to cease operations and get out of Sudan within two weeks, relief officials in Nairobi said.

Jacob Akol, spokesman for World Vision International in Nairobi, said Tuesday that his agency was one of those ordered out. He also said Sudan had ordered out the Association of Christian Relief Organizations Serving Sudan, a Nairobi-based conglomerate of American relief agencies.

Akol said World Vision, based in Monrovia, Calif., was appealing the order. "We have been asked to leave but by exactly who in the government and why is what we are trying to find out," he said.

Akol said a World Vision representative had flown to Khartoum, the capital of Sudan, to try to sort out the problem. He said World Vision has three Americans and several Sudanese working on a small food relief project in the southwestern town of Wau.

Other relief sources, speaking on condition of anonymity, said at least a dozen other relief agencies had been asked to leave, all of them American or European. An official at the Sudanese Embassy in Nairobi said 16 organizations had been asked to leave Sudan, but he would not identify the groups. He spoke on condition of anonymity.

Sudan's attorney general, Abdel Mahmoud Haj Saleh, announced in July that the government would close more than 20 foreign relief organizations. He charged that the agencies cooperate with the rebel Sudanese People's Liberation Army.