Jean-Christophe Sandoz, head of the ICRC delegation in Sudan, said prisoners were returned on an aircraft chartered by the aid group. He stressed the ICRC was acting in its capacity as a neutral intermediary. The aid group helped repatriate 13 POWs released by the South Sudanese government in April.
A comprehensive peace agreement signed in 2005 ended a brutal civil war and lead to South Sudan's independence last year. Border issues, ethnic fighting and disputes over oil have threatened the peace deal, however.
Aid agencies estimate tens of thousands of refugees in Sudanese border states have fled to South Sudan to escape simmering conflict. Sean Casey, an aid director for the International Medical Corps U.K., told The Guardian newspaper heavy rains have made parts of the region inaccessible.
Sudanese and South Sudanese leaders made progress in settling outstanding issues during talks in Ethiopia. Both sides are under pressure from the United Nations to resolve differences peacefully.