( CNN ) -- Three Senegalese peacekeeping officers were killed in an attack on a convoy in Darfur on Sunday , the United Nations said . An unidentified armed group ambushed a water convoy on its way to a regional headquarters of the joint African Union-United Nations peacekeeping force , a U.N. statement said . One truck was hijacked but recovered later . Seven Tanzanian peacekeepers were killed in a similar ambush in July . The UN estimates as many as 300,000 people have been killed and almost 3 million people have been displaced from their homes since a conflict began in 2003 in Darfur , a region of Sudan along the border with the new nation of South Sudan . Widespread atrocities have occurred during fighting between Sudan 's government forces and militias and other rebel groups . The peacekeeping operation began in 2007 . UN Secretary-General Ban Ki-moon called on the government of Sudan to apprehend the attackers . Mohamed Ibn Chambas , special representative for the peacekeeping force , commended the Sudanese military for pursuing and firing on the assailants . `` Such incidents are a reminder to all of us of the great price everyone pays in the absence of peace . Our peacekeepers have made the ultimate sacrifice while attempting to bring peace to Darfur , '' Chambas said .
Slain peacekeepers were from Senegal . The UN mission in the Central African Republic said it was investigating reports of a massacre at an army camp near Bangui, where troops loyal to Seleka rebels have been accused by residents and human rights Secretary-general calls on Sudan to apprehend attackers . Decade of conflict in Darfur has killed up to 300,000 , displaced almost 3 million .