South Sudanese refugees flown home from Khartoum
The first planeload of refugees stranded for months in a camp in Sudan has arrived in South Sudan.
The 164 people have arrived in Juba after flying from Khartoum, where they had been taken by bus from their camp.
They are among up to 500,000 southerners who lost their Sudanese nationality when South Sudan gained independence last year.
The two countries have recently come close to all-out war, particularly in oil fields near their common border.
Those who have flown home are part of a group of some 15,000 southerners stranded in Kosti, White Nile state. They were initially told they must leave Sudan by 5 May, before the deadline was extended until 20 May.
Sudan's authorities refused to let them travel south by barge, citing security concerns, so they instead travelled the 300km (190 miles) north from Kosti by bus over the weekend to Sudan's capital, from where their flights departed.
Since South Sudan gained independence, thousands of southerners have been sacked from Sudan's civil service.
One of those who boarded the first plane told AFP news agency she had never been to her "homeland" before.
Main disputes between the two Sudans
- The amount the South should pay Sudan to use its oil pipelines
- Demarcating the border
- Both sides claim Abyei
- The rights of each other's citizens now in a foreign country - there are estimated to be 500,000 southerners in Sudan and 80,000 Sudanese in the South
- Each accuses the other of supporting rebel groups on its territory
"It is my first time to the South. I was born here," said Cecilia Peter, 27, who had been sacked as a teacher.
Some of the refugees are said to be concerned that they had to leave their luggage behind in Kosti.
A special camp has been set up for the returnees near the South Sudan capital, Juba. They will then be dispersed to their areas of origin, AFP reports.
More flights are scheduled in the coming days, according to the International Organization for Migration.
South Sudan, where most people are Christians or follow traditional religions, gained independence after decades of conflict with the Arab-dominated, mainly Muslim north.
Several million people went north during the conflict - either fleeing the fighting or to seek work.
Hundreds of thousands went home to vote in the 2011 independence referendum but some half a million remain.
The two countries are still negotiating about whether they will be allowed to stay in Sudan or if they will all be forced to go to the South.
There are also believed to be some 80,000 Sudanese living in the South.
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.