Fighting for water for horses and livestock is common in central Sudan
An estimated 250 people in central Sudan have been killed during a week of clashes between nomadic groups.
Sudan's interior minister said the dead included 75 policemen who were attacked by about 3,000 armed horsemen as they tried to intervene in the battles.
Conflict over grazing land and cattle is common in the semi-arid region of Southern Kordofan.
But the BBC's Peter Martell in Sudan says the scale of the violence and the numbers killed have shocked many.
The battles started last week between two Arab rival nomadic ethnic groups - the Misseriya and the Rizeigat.
Our correspondent says the groups have a long history of fighting over access to drinking water for their horses and their livestock.
But this was no ordinary tussle over land or animals, he says.
With the fighting escalating, Sudanese police moved in to try and establish a buffer zone between them.
But the police then found themselves attacked by armed Rizeigat horsemen.
Interior Minister Ibrahim Mahmoud Hamad told Sudan's state news agency that those responsible would be brought to justice and that the authorities would take steps to disarm civilians.
Officials say that the fighting has now calmed down but the situation remains tense.
South Kordofan, sandwiched between Darfur and southern Sudan, has long been unstable.
It was an area of major conflict during Sudan's two-decade-long north-south civil war, which ended in a peace deal four years ago.
Our reporter says the fighting follows several heavy tribal clashes across Sudan in recent months.
He says those conflicts are causing growing concern amongst analysts and officials that it will encourage a divisive atmosphere and further insecurity ahead of national elections due next February.