President Omar al-Bashir gives South Sudan his blessing
Sudan's President Omar al-Bashir has pledged his support to South Sudan, which gains its independence from the north on Saturday.
"We will bless our brothers in the south over their country and we wish them success," he said, state TV quoted him as saying.
The president said he wanted the new country to be "secure and stable".
But he warned "brotherly relations" depended on secure borders and non-interference in each others' affairs.
Southerners voted to split from Sudan in a referendum last January, following the 2005 peace deal that ended more than two decades of civil war - in which an estimated 1.5 million died.
There had been fears that war could resume after recent fighting in two border areas, Abyei and South Kordofan, which has forced some 170,000 people from their homes.
But separate deals in recent weeks, and the withdrawal of rival forces from the border, have calmed tensions.
"We reiterate our readiness to stand with them and support them because they want their country," said Mr Bashir, who is due in the southern capital, Juba, on Saturday for the independence celebrations.
"We will not interfere in your internal affairs. Likewise, we will not allow you to interfere in our internal affairs," he warned.
"We are capable of responding but we do not want to.
He said he wanted "good neighbourliness and friendship", as well as good trade links.
Analysts say the priority for Mr Bashir's government in its relations with South Sudan will be to negotiate a favourable deal on oil revenue, as most oilfields lie in the south.
At present, the revenues are being shared equally.
Khartoum has some leverage, as most of the oil pipelines flow north to Port Sudan on the Red Sea.
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.