NAIROBI, Kenya (AP) _ Sudanese government aircraft bombed a hospital operated by an international aid agency working in southern Sudan, aid workers said Thursday.

Three of six bombs hit the facility, completely destroying the immunization block and extensively damaging the operating room and the outpatient section, Doctors Without Borders said in a statement.

No one was killed in Wednesday's air raid on Kajo Keji, near the Ugandan border.

``This is a deplorable act which clearly targets civilians and medical assistance to the civilian population,'' said Ettore Larici, the head of the agency's mission in southern Sudan.

The area is controlled by the rebel Sudan People's Liberation Army.

Doctors Without Borders said the bombing is a violation of fundamental principles of international humanitarian law.

``The government of Sudan is obliged under these principles to respect the protection of the wounded,'' the statement said.

The agency has operated the hospital, which serves 90,000 people, since September 1997. Thirty of the 60 beds are reserved for children.

In the last six weeks, Sudanese government aircraft have bombed civilian hospitals in the rebel-held towns of Yei, Nimule, Labone and Chuckdum.

The predominantly Christian, animist and African southerners took up arms in 1983 to press for increased autonomy and development in the region, which is about the same size as Texas.

At least 1.5 million people have died in the fighting and accompanying famines.