More than 99 percent of voters in Sudan's south chose to separate from the north in a plebiscite intended to end decades of civil war, a referendum official said on Sunday announcing preliminary results.

"The vote for separation was 99.57 percent," Chan Reek Madut, the deputy head of the commission organising the January 9 week-long referendum told cheering crowds in the first official announcement of results.   

The figure did not include voters in north Sudan and other countries, a small proportion of the electorate. Final results are expected early next month.

The vote was promised in a 2005 peace deal which ended decades of north-south conflict, Africa's longest civil war which cost an estimated 2 million lives killed, forced 4 million to flee and destabilised the region.

Five of the 10 states in Sudan's oil-producing south showed a 99.9 percent vote for separation and the lowest vote was 95.5 percent in favour in the western state of Bahr Al-Ghazal which borders north Sudan. - Reuters