U.N. Secretary General Ban Ki-moon on Wednesday condemned an attack on a police convoy of African Union and U.N. peacekeepers that left seven police officers injured. “The secretary-general condemns the attack by unidentified armed assailants against a U.N.-African Union mission in Darfur,” Ban's spokeswoman Marie Okabe said. The peacekeepers, part of a five-vehicle police convoy, came under heavy gunfire in the afternoon near Sakali, an area located close to the El-Sherif camp for internally displaced persons (IDPs) and 16 kilometers south of Nyala, the capital of South Darfur state. They were returning to their base in Nyala, following a confidence-building patrol in the vicinity of the IDP camp, when several unknown assailants armed with assault rifles suddenly opened fire on the convoy, according to a news release issued by the peacekeeping mission, known as UNAMID. “The secretary-general calls on the government of Sudan to launch an immediate investigation into this incident and to ensure that the perpetrators are swiftly identified and brought to justice,” Okabe added. There are more than 15,000 peacekeepers in Darfur as part of the joint U.N.-AU force.