The Sudanese government's capture of the southern rebel headquarters at Torit has propelled the nine-year bush war into a new phase and may wipe out progress made at recent peace talks.
Government troops overran the Sudan People's Liberation Army base near the Ugandan border Monday. The attack was a climax to Khartoum's biggest dry-season offensive of the war. It has captured 14 towns since March.
The southern rebels still control large areas of Eastern and Western Equatoria states and say they will regain lost ground when the rains return.
UN officials voiced concern that 150,000 Sudanese refugees would flee to Uganda as a result of Torit's capture. About 22,500 Sudanese fled to Kenya last month.