( CNN ) -- At least seven U.N. peacekeepers were killed and 17 others were injured in an ambush Saturday morning near their base in Manawashi , north of the South Darfur regional capital of Nyala , a U.N. spokesman said . U.N. Secretary-General Ban Ki-moon expressed outrage about the attacks and identified the killed peacekeepers as Tanzanians , a spokesman said . A group of vehicles manned by troops and police of the African Union-United Nations Hybrid Operation in Darfur ( UNAMID ) was attacked . It was the third attack on the unit in three weeks , the spokesman said . The secretary-general `` expects that the Government of Sudan will take swift action to bring the perpetrators to justice , '' the spokesman 's statement said . The Darfur region is located in Sudan along the border with the new nation of South Sudan . The convoy came under heavy gunfire , and fighting continued as peacekeepers were vastly outnumbered , said Chris Cycmanick , acting spokesman for the U.N. Mission in Darfur . There has not been any claim of responsibility for the attack . Violence has plagued Darfur for a decade . The United Nations estimates as many as 300,000 people have been killed and almost 3 million people have been displaced from their homes since the Darfur conflict broke out in 2003 . Widespread atrocities have occurred during fighting between Sudan 's government forces and militias and other rebel groups . The African Union-U.N . Hybrid Operation was established as peacekeepers in 2007 , with the mission 's headquarters in El Fasher , North Darfur .
The seven killed U.N. peacekeepers are Tanzanians . U.N. Secretary-General Ban Ki-moon expresses outrage . Attack is third in three weeks on African Union-United Nations Hybrid Operation in Darfur .