The UN has warned about an upsurge in violence in Sudan’s Darfur region, saying some 50,000 people had been displaced since the end of February.
Peacekeepers and aid agencies had been blocked from entering affected areas, UN human rights chief Navi Pillay said.
Much of the violence is between rival Arab groups, although rebel and government forces are also involved, a BBC correspondent reports.
Darfur has been hit by conflict since 2003, when rebels took up arms.
Two million people have already been displaced by the conflict.
The International Criminal Court has issued an arrest warrant for Sudan’s President Omar al-Bashir, accusing him of committing war crimes and genocide against black African communities in Darfur.
He denies the charge.
On Monday, UN Secretary-General Ban Ki-moon said was deeply concerned about the escalating violence in Darfur, and he urged all parties to immediately stop hostilities.
Ms Pillay said some 45 villages were reportedly targeted in the Um Gunya area, about 250km (155 miles) south of Fasher, the capital of North Darfur state.