South Sudan's oil facility 'bombed by Sudan'

South Sudan has accused Sudan of bombing one of its oil facilities, despite recent moves to defuse the conflict between the two countries.

A number of blasts have been heard in South Sudan, with a military official telling the BBC that the Unity oil field was targeted.

The government in Khartoum has so far made no public comments on the claim.

On Friday, South Sudan said it was withdrawing its troops from the disputed Heglig oil field.

Sudan claimed it had regained the area by force.

Heglig is internationally accepted to be part of Sudanese territory - although the precise border is yet to be demarcated.

Other issues dividing the two countries are the transit fees the South should pay Sudan to use its oil pipelines and the status of the province of Abyei.

The escalating fighting and rhetoric between the two sides over the past week has led to fears of all-out war.

US President Barack Obama has urged the presidents in Khartoum and Juba to "have the courage" to return to the negotiating table and resolve their differences peacefully.

South Sudan seceded last July following a 2005 peace deal that ended a two-decade civil war in which more than 1.5 million people died.

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. The residents of war-affected Darfur and South Sudan are still greatly dependent on food aid. Far more than in northern states, which tend to be wealthier, more urbanised and less reliant on agriculture.