Rebels in the Democratic Republic of Congo have taken two aid workers hostage after an attack on a remote village in the country's volatile east, a spokesman for the United Nations peacekeeping force said Monday. The rebels attacked the tin-mining village of Walikale late in the morning Monday, seizing five workers for U.S.-based aid group International Medical Corps, Madnodje Mounaubai, spokesman for the U.N. force, told Reuters. Three Americans that were among the hostages were quickly released, while a Georgian and a Congolese remained captive, he said. A joint force of U.N. and Congolese troops set out in pursuit of the rebels, he said, adding he was not able to give the identity of the rebels. The eastern part of the Democratic Republic of Congo is plagued with a number of armed groups who continue to operate there despite the presence of the largest U.N. peacekeeping force, the United Nations Organization Stabilization Mission in the Democratic Republic of the Congo (MONUSCO), which has some 18,000 troops.