United Nations human rights chief Volker Türk has said both groups in the conflict in Sudan have trampled upon international humanitarian law.
Opening an emergency session of the UN Human Rights Council in Geneva, Türk urged countries with influence in Africa to help end the violence.
Reports say Fighting has been continuing in the capital, Khartoum, and in the city of Omdurman while witnesses in Khartoum reported air raids and counter-fire from anti-aircraft guns.