Sudan: Abyei ethnic clashes mar peace deal
At least 10 people have been killed in fighting between rival ethnic groups in Sudan's disputed oil-producing region of Abyei, officials say
The clashes between Arab nomads and the southern Dinka Ngok people are the first since a deal between the two sides was agreed last month.
Abyei lies on the border between north and south Sudan.
The region did not take part in last month's referendum in which southerners voted to split from the north.
Abyei is due to vote on whether to join the north or south at a later, unspecified date.
The Dinka Ngok think it belongs in the south, while the nomadic Arab Misseriya see it as northern.
The heart of their dispute is about grazing rights for cattle, which are central to both communities' traditions and economies.
Both sides accused each other of starting the recent clashes.
Deng Arop Kuol, the chief administrator for Abyei from the Dinka Ngok community, told Reuters news agency a Misseriya group had attacked a settlement in the early hours of Sunday morning.
But senior Misseriya official Saddig Babo Nimr told the agency the southern army had started the fighting by attacking a nomadic camp.
Officials have warned the death toll could rise.
"There is still fighting going on. The situation is very bad, and we cannot stop to count the dead," Mr Kuol told AFP news agency.
UN troops in Abyei have been boosted over the last few months because of the tensions.
North and south Sudan have suffered decades of conflicts driven by religious and ethnic divides, with an estimated 1.5 million people killed in the civil war.
The referendum on southern secession was agreed as part of the 2005 deal to end the 21-year civil war.
Both Sudan and the South are reliant on their oil revenues, which account for 98% of South Sudan's budget. But the two countries cannot agree how to divide the oil wealth of the former united state. Some 75% of the oil lies in the South but all the pipelines run north. It is feared that disputes over oil could lead the two neighbours to return to war.
Although they were united for many years, the two Sudans were always very different. The great divide is visible even from space, as this Nasa satellite image shows. The northern states are a blanket of desert, broken only by the fertile Nile corridor. South Sudan is covered by green swathes of grassland, swamps and tropical forest.
Sudan's arid north is mainly home to Arabic-speaking Muslims. But in South Sudan there is no dominant culture. The Dinkas and the Nuers are the largest of more than 200 ethnic groups, each with its own languages and traditional beliefs, alongside Christianity and Islam.
The health inequalities in Sudan are illustrated by infant mortality rates. In South Sudan, one in 10 children die before their first birthday. Whereas in the more developed northern states, such as Gezira and White Nile, half of those children would be expected to survive.
The gulf in water resources between north and south is stark. In Khartoum, River Nile, and Gezira states, two-thirds of people have access to piped drinking water and pit latrines. In the south, boreholes and unprotected wells are the main drinking sources. More than 80% of southerners have no toilet facilities whatsoever.
Throughout the two Sudans, access to primary school education is strongly linked to household earnings. In the poorest parts of the south, less than 1% of children finish primary school. Whereas in the wealthier north, up to 50% of children complete primary level education.
Conflict and poverty are the main causes of food insecurity in both countries. In Sudan, many of the residents of war-affected Darfur and the border states of Blue Nile and South Kordofan, depend on food aid. The UN said about 2.8m people in South Sudan would require food aid in 2013. The northern states tend to be wealthier, more urbanised and less reliant on agriculture.