U.N. Secretary-General Ban Ki-moon on Wednesday condemned the killings of three Indian peacekeepers who were ambushed at their base in eastern Democratic Republic of Congo The three were serving with the U.N. Stabilization Mission in DR Congo, known as MONUSCO. At least six other peacekeepers were injured in the early morning attack by a group of armed rebels. "The secretary-general condemns the assault and calls on the government of the Democratic Republic of the Congo to launch an immediate investigation into this incident and ensure that the perpetrators are swiftly identified and brought to justice," Ban's spokesman, Martin Nesirky, told reporters. The United Nations has a 16,000-strong peacekeeping force in DR Congo, based mostly in the volatile east. The Congolese government wants all peacekeepers withdrawn by August next year, saying it is capable of maintaining law and order and protecting civilians.