More than 60 percent of voters have already taken part in south Sudan's referendum, ensuring the result of the vote will be valid, a senior southern official said on Wednesday.
The commission organising the vote was not immediately able to confirm on Wednesday that the 60 percent threshold -- the turnout necessary for the referendum to be declared valid -- had been achieved, as the week-long poll entered its fourth day.
The announcement came as northern and southern leaders called two crisis meetings to resolve a surge of violence in contested border regions that has marred the plebiscite.
"I know very well that by three days of voting the 60 percent threshold has been passed," Anne Itto, from the south's ruling Sudan People's Liberation Movement (SPLM), told reporters in the southern capital Juba.
More than 50 percent of those who do vote need to choose independence in order for the south to secede.
Preliminary results in the referendum are expected around the beginning of February. The underdeveloped south makes up a quarter of Sudan's land mass but has just 60 km (37 miles) of paved roads.
At least 46 deaths have been reported since Friday in clashes between northern Arab nomads and southern police, youths and refugees.
"We will see if they can reach an agreement ... Without hope you can't live," said Deng Arop Kuol, the southern administrator for the contested oil-producing area of Abyei, a flashpoint of past north-south fighting.
Sudan turnout 'passes 60 pct threshold'
The commission organising the vote was not immediately able to confirm on Wednesday that the 60 percent threshold had been achieved.