The African Union's Peace and Security Council arrives in Sudan on Sunday to meet African peacekeepers serving in the troubled Darfur region, official media said, as rebels claimed a fresh attack.
The rare visit comes 10 years after insurgents from black tribes began their uprising, and after inter-Arab violence since this January has led to the worst displacement of the population in several years.
African Union peacekeepers have served for five years in the UNAMID mission run jointly with the United Nations.
Sudan's official SUNA news agency reported on Saturday that the delegation will visit UNAMID headquarters in the North Darfur state capital, El Fasher, and hold talks with the state governor.
The AU mission is to also visit Kebkabiya, a town west of El Fasher where the UN says thousands of people have sought refuge following fighting between two Arab tribes in the Jebel Amir gold mining area in January and February.
African Union officials will then travel to the South Darfur state capital of Nyala for talks with the governor.
South of Nyala, a large number of government soldiers and militiamen were killed on Friday during a rebel attack on their convoy in the Abga Rajel area, the Sudan Liberation Army's Minni Minnawi faction said.
The rebels destroyed two armoured vehicles and captured prisoners, Minnawi faction spokesman Adam Salih Abaker said in a statement on Saturday.
Sudan's army spokesman could not be reached for comment.
"There is a lot of rebel movement in the areas south of Nyala," a humanitarian source told AFP, adding that the road between Nyala and Girayda "is particularly unsafe."
The lack of security has affected aid operations, said the source, asking for anonymity.
Attempts to reach the African Union for comment about its Darfur mission were unsuccessful.
But an African diplomat told AFP that the 15-member council had visited at least once before over the past two years.
He said the trip will help highlight "worrying" developments in Sudan's far-west region, where almost 21,000 soldiers and police serve with UNAMID.
Darfur's top official, Eltigani Seisi, told AFP in February that the security situation "has improved a lot" across most of the region, where the UN says 1.4 million displaced people still live in camps.