Polling centres in South Sudan have closed after a week-long vote on independence from the north.
Former US President Jimmy Carter, who is leading a mission observing the vote, says turnout could reach 90% and it seems likely the south has voted for independence.
Final results are due before 15 February but could be announced as early as the beginning of the month.
The vote caps a 2005 peace agreement that ended decades of civil war between the mostly Muslim north and the south, where most follow Christianity and traditional beliefs.
More than 182,000 exiled southerners have returned to the south since the end of October, according to UN figures, many of them fearing repercussions in the north after the vote.
The oil-producing south makes up a quarter of the country's land.