Sudan and South Sudan leaders agree basic freedoms
Sudan and South Sudan have agreed a framework agreement to give their citizens basic freedoms in both nations, African Union mediators say.
They have agreed to allow citizens of the other state to live, work and own property on either side of the border, and travel between the two nations.
Analysts say deals have been broken in the past, and the two sides have left space to wriggle out of this accord.
Bitter disagreements over disputed land and oil also remain unresolved.
However, officials said Sudanese President Omar al-Bashir would make his first visit to South Sudan since the country gained independence last July.
He is expected to make the trip in the next two weeks.
The framework deal said nationals of each state would be given "freedom of residence, freedom of movement, freedom to undertake economic activity and freedom to acquire and dispose property".
Two months ago, Khartoum had threatened to treat South Sudanese as foreigners from 8 April unless they obtained residency or work permits.
Some 350,000 southerners have moved to South Sudan since October 2010, after decades living in the north, but some 700,000 southerners remain, according to the UN.
The BBC's James Copnall, in Khartoum, says that the accords can, at best, be seen as agreements in principle.
A series of signed deals have not been respected in the past and the talks have yet to lead to a breakthrough in the key issue of oil, our correspondent says.
In January, South Sudan shut down all of its oil fields in a row over the fees Sudan demands to transit the oil.
South Sudan depends on oil sales for 98% of state revenues, but has pledged not to restart production until a deal is reached.
Parts of the countries' common border also remain in dispute.
In February, the two states agreed to demarcate most of the border within three months, although this would exclude five disputed areas.
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.