Representatives from the different parties are observing the count
Vote counting has started in Sudan after the five-day landmark elections.
They were the first multi-party polls since 1986 and part of a north-south deal to end two decades of war.
There have been widespread allegations of ballot-rigging, both by supporters of President Omar al-Bashir in the north, and by ex-rebels in the south.
Former US President Jimmy Carter, whose organisation has been helping monitor them, told the BBC it was too early to judge whether they were free and fair.
Results are not expected for several days. But President Omar al-Bashir is expected to win another five years in office as his two main challengers withdrew from the race just before the vote, alleging fraud.
First multi-party polls in 24 years
Polls to elect president and 450-member national assembly, as well as governors and legislative bodies for 25 states
Complicated process, with some in the south having to cast 12 different votes
Several opposition parties have boycotted the polls, alleging fraud
Results due next week
Southern Sudan due to hold independence referendum in January 2011
Mr Carter acknowledged there were problems with voting, but said he could not be sure whether they had given any particular candidate an advantage.
He said the fact that a significant part of the opposition had announced a boycott would not affect the legitimacy of the poll.
"As you know, almost all the candidates remained in the race until the end of the campaigning period was over," he told the BBC's World Today programme.
This meant the ballot papers had been printed with all the candidates' names on them.
"The National Election Commission unanimously told us that if any candidate gets a vote, whether that party has withdrawn or not, the candidate's vote will be counted.
"And if any of the candidates get a majority of the vote they will be declared to have won the election and they can hold office if they wish."
Mr Bashir, who is wanted by the UN for war crimes in Darfur, where a low level conflict continues, has asked rival parties to join his government if he wins.
Just as he is certain to win the presidential vote, the southern former rebels - the Sudan People's Liberation Movement (SPLM) - are likely to dominate the polls in the south.
The country's ruling party said on Thursday that soldiers from the semi-autonomous south had killed at least five of its supporters in the first reported incident of deadly violence during polling.
In Darfur, though, the authorities were keen to highlight there was no major security incident during the elections.
However areas controlled by rebels did not vote, and hundreds of thousands of internally displaced people did not register.