The U.N. says three aid workers from the charity Save the Children were freed less than a week after being kidnapped in eastern Congo.

The U.N. Office for the Coordination of Humanitarian Affairs in Congo said Tuesday on Twitter that the three Congolese staffers kidnapped March 2 in North Kivu province had been released, without providing details.

The Center of Study for the Promotion of Peace, Democracy and Human Rights, a local group that tracks rebel violence in the region, said the aid workers were being transported to safety by Save the Children after being freed around 8 a.m.

Save the Children could not be reached Tuesday. It was not immediately clear who was behind the kidnapping. Multiple armed groups are active in eastern Congo.