Residents and health officials in southern Sudan say at least 15 people have been killed after a dispute over land in Blue Nile state escalated.
The clashes were reportedly sparked by arguments between members of the Hausa people and rival groups in the small town of Wad al-Mahi, about 500 km (310 miles) south of the capital, Khartoum.
Residents described hearing intense gunfire and said homes had been torched.
Staff at the town clinic said a number of bodies had been brought in.
The violence broke out despite a heavy security presence in the area, which is subject to an overnight curfew following a land dispute last week in which more than a dozen people were killed.