Darfur has been mired in conflict since 2003 when ethnic rebels mounted an insurgency against the Arab-dominated government
Unidentified gunmen ambushed a patrol of UN-African Union peacekeepers in Sudan's western Darfur region on Thursday, seizing weapons and ammunition from them, the mission said.
The incident took place in North Darfur state, in western Sudan, where the UN-AU mission (UNAMID) has been deployed since 2007.
"The perpetrators, who greatly outnumbered UNAMID's peacekeepers, seized one machine gun, four rifles and rounds of ammunition. One peacekeeper was injured in the incident," the mission said in a statement, without giving further details.
"UNAMID condemns such attacks on its personnel" and is investigating with the Sudanese authorities, the statement said.
Darfur has been mired in conflict since 2003 when ethnic rebels mounted an insurgency against the Arab-dominated government of President Omar al-Bashir, complaining they were being politically and economically marginalised.
Bashir has been indicted by the International Criminal Court over alleged war crimes, crimes against humanity and genocide charges related to the conflict.
UNAMID deployed to the region to protect civilians and secure humanitarian aid.
But gunmen sporadically attack the peacekeepers and in 2014 Khartoum told UNAMID to prepare to leave after the mission's attempts to investigate the reported rape of 200 women and girls in a North Darfur village sparked government anger.
Some 300,000 people have been killed and nearly 2.5 million displaced in the conflict, the UN says, although the government puts the death toll at 10,000.