Sudan's President Omar al-Bashir said Khartoum accepts the south's choice of independence in January's referendum, hours before final results were poised to confirm a landslide for secession on Monday.
"We will announce today, in front of the world, that we accept the result and we respect the choice of southern Sudanese," Bashir said in a speech to women and students at the headquarters of his ruling National Congress Party.
"The result of the referendum is well known. South Sudan has chosen secession. But we are committed to the links between the north and the south, and we are committed to good relations based on cooperation."
The January 9-15 referendum defied expectations by taking place on time and largely without incident, despite the major logistical challenges facing the organisers and fears that the Khartoum government might try to block a process certain to split Africa's largest nation in two.
The final results of the landmark vote were due to be confirmed at a ceremony in Khartoum later on Monday, attended by Bashir and southern leader Salva Kiir, one week after preliminary results showed almost 99 percent of south Sudanese voted to split with the north.
In the southern capital Juba, small celebrations were already underway at former rebel leader John Garang's mausoleum, where hundreds had gathered despite the stifling heat.
"This is our day for freedom. We are ready to celebrate all night long," said Santino Machar, a student.
Bashir, who had already recognised the prospect of partition, renewed his commitment to protecting southerners in the north, and pledged to work to resolve all outstanding issues between the north and south ahead of the creation of Africa's newest state in July.
But he warned that any resolution to the future of the flashpoint border region of Abyei must accommodate the rights of the Arab nomads, who migrate there each year looking for pasture for their cattle.
"We will not be a part of any solution to that does not reserve the rights of the Misseriya. Voting in the Abyei referendum is the right of all citizens, and there are no second-class citizens because they are nomads," he said.
The future status of Abyei is the most sensitive issue that Khartoum and Juba must resolve ahead of southern independence, with oil-revenue sharing, border demarcation and citizenship also on the agenda.
More than 37 people died in clashes there in January, amid deadlock over who should be eligible to vote in a plebiscite that was due to coincide with the southern referendum on whether the region stays with the north or joins the south.
Abyei is home to the Ngok Dinka tribe, who are expected to support joining an independent south, while the Misseriya largely support the north.
At the African Union summit in Addis Ababa last week, Kiir reiterated the SPLM's stand that the region should hold its delayed vote or be handed to the south by a presidential decree.
The referendum on southern independence was the centrepiece of a 2005 peace deal that ended a devastating 22-year conflict between the largely African Christian south and the mainly Arab Muslim north that killed around two million people.
In contrast to the jubilation in the south, the outcome of the referendum has caused sadness and at times anger in the north, where student activists organised street protests last week calling for regime change that were swiftly suppressed by the security forces.
"Today is a sad day for all the citizens of north Sudan. It's a tragedy somehow," said a 23-year-old student activist, who only gave his name as Mohammed.