|Most analysts expect the south to vote to break away from northern Sudan [Reuters]
Southern Sudan's governing party has officially said it will support secession from the north in an independence referendum planned for next year.
The announcement on Saturday by the Sudan People's Liberation Movement (SPLM) is significant because it is at odds with the terms of the 2005 peace agreement that ended the south's civil war with northern Sudan.
In that deal, the SPLM agreed to work with the north's ruling National Congress Party (NCP) towards unity.
Anne Itto, from the SPLM, said: "Since unity has not been made attractive, we are promoting what our people choose because we are following the people."
Asked what she meant, Itto answered "separation".
Her comments prompted an angry warning from the north, with Rabie Abdelati, Senior NCP official, accusing Itto of breaking the terms of the peace deal.
"They [the SPLM] are now working for secession regardless of the result of the referendum ... The referendum will be nominal, illegal. I do not think that the NCP should recognise any process or any result that comes out of it," he said.
Itto is from the party's dominant southern sector. Yasir Arman, from the party's northern sector, declined to comment.
The referendum, which will decide whether the oil-producing south should secede or stay in Sudan, is scheduled for January 9.
The vote is a key part of the 2005 Comprehensive Peace Agreement (CPA) that ended Africa's longest-running civil war, in which an estimated two million people were killed.
Most analysts expect the south to vote to break away and split the country in two.
Organisers of the vote said on Wednesday that almost three million people have signed up to vote.
Talks to resume
Itto said that progress was slow on the remaining key issues that still need to be agreed between north and south before the polling day.
These include the final demarcation of the border between north and south, the sharing of oil revenues and the status of southerners in the north and northerners in the south if the region votes to break away.
Itto said that there had so far been "little progress" on these issues.
"We have had several meetings with no success at all, not in security, not in international treaties, not in finance, economic issues, natural resources, not even in citizenship.
"If you add all that together it is a clear indication as to how NCP doesn't want to get to referendum," she added.
Talks are due to resume on Monday.