Satellite tracks Sudan oil damage
Satellite pictures of the disputed border area occupied by South Sudan for 10 days suggest key oil installations have been badly damaged.
The pictures appear to show significant parts of the Heglig oilfield in Sudan are no longer operating.
They were analysed by the US-funded Satellite Sentinel Project (SSP), which says it is impossible to know who was responsible for the damage.
Sudan and South Sudan have accused each other of attacking oil facilities.
Access to the disputed border region around Heglig is limited, making it difficult to verify what is happening in the area.
The pictures provided by SSP suggest that the oil industry has been deliberately targeted.'Runway lengthened'
One picture appears to show an oil collection point at the end of two pipelines has been destroyed, leaving charred wreckage over a wide area.
SSP says it is impossible to know whether the damage was done by aerial bombing or ground attacks.
Others show tanks, smoke rising from explosions that are consistent with aerial bombing, and cratering.
There are also pictures showing that the Sudan Air Force runway in South Kordofan has been paved and lengthened to allow Antonov bombers to land there.
SSP, which was set up to campaign against the return to full-scale civil war between the two countries, used pictures from DigitalGlobe satellites, which were analysed by the Harvard Humanitarian Initiative.
SSP receives funding from the Not on Our Watch project, founded by US activists including the actors George Clooney, Brad Pitt and Matt Damon.
On Friday South Sudan said it would withdraw from the Heglig area, while Sudan said its forces had re-taken control of the area.
The area north of the disputed border provides most of of Sudan's oil output, and is a crucial part of its economy.
BBC regional analyst Grant Ferrett says the pictures suggest the after-effects of South Sudan's brief occupation could last some time, further undermining relations between the two countries.
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.