Sudanese authorities say tribal clashes between Arabs and non-Arabs in the country's South Darfur province have left at least 30 people dead and a dozen wounded.
A statement from the Prime Minister's office says the clashes erupted on Tuesday and continued into Wednesday but have since subsided.
The fighting poses a significant challenge to efforts by Sudan's transitional government to end decades-long rebellions in areas of the country including Darfur.
Tensions between the Arab and non-Arab tribes date back to the Darfur conflict that began in 2003, when ethnic Africans rebelled, accusing the Arab-dominated Sudanese government of discrimination.
The government of former President Omar al-Bashir in the capital Khartoum at the time was accused of retaliating by arming local nomadic Arab tribes and organizing them into a militia known as the Janjaweed and unleashing them on civilian populations.
The militias became notorious for massacres and rapes.