Seven peacekeepers of the UN- African Union Mission in Darfur (UNAMID) were killed and 17 others injured Saturday in an attack by an unidentified group on their patrol in Sudan's South Darfur state, a UNAMID source told Xinhua.

"An unidentified group ambushed the UNAMID patrol at Khur Abbashy area in South Darfur State. The attack resulted in the killing of seven soldiers and injuring of 17 others," the source said on condition of anonymity.

The two sides exchanged fire for about an hour, the source said, adding that UNAMID is currently making a preliminary evaluation for the situation to determine the reasons and motives behind the incident.

Around 24,000 UNAMID soldiers are shouldering the task of peacekeeping in the Darfur region which has been suffering from a civil war since 2003.

Since its deployment in early 2008, the mission has lost more than 40 of its personnel in attacks by unidentified gunmen in the region.