Senegal's leader Abdoulaye Wade has admitted that he may not have got enough votes to avoid a run-off - but he still said "everything is possible".
Unofficial results - with more than half of the vote counted - give Mr Wade 32%, with his closest rival and former Prime Minister Macky Sall on 25%.
President Wade previously predicted a "crushing" first-round victory in his contentious third term.
Mr Wade, 85, was booed as he cast his vote on Sunday in the capital, Dakar.
Everything still possible
"To all of my supporters, my allies, my sympathisers, I ask that you remain mobilised," Mr Wade read from a prepared statement as he met reporters for the first time since the elections.
"At this very hour... everything is still possible - victory or a run-off," he said.The normally talkative leader appeared subdued and did not take questions from reporters, the Associated Press news agency reports.
The BBC's Umaru Fofana in Dakar says the president also said that he would be opening talks with opposition candidates in case of a second round.
Mr Wade lost in his own constituency in the middle-class Dakar neighbourhood of Point E, Senegal's national APS news agency reports.
Mr Sall believes that "a second round is inevitable, we have won the biggest departments in the country."
The 50-year-old geologist and mayor of the western town of Fatick also warned against rigging.
Analysts said Mr Wade would struggle in the second round, when the field narrows to two candidates.
Mr Sall, who is running for the first time, told the BBC that it would be "easy" to win in the second round, as he expected all opposition supporters to unite behind him.
The electoral commission has yet to publish any provisional results, which are being announced by local media as they trickle in from polling stations.
The commission says it will publish its first results later on Tuesday.
The date scheduled for a possible second vote is 18 March.
Senegal's constitutional court ruled that Mr Wade could stand again on the grounds that his first term had not counted since it began before the two-term limit was introduced in 2001.
Mr Wade's decision to stand again sparked weeks of violent protests - leading to about six deaths - although polling day itself was largely peaceful.
Senegal, a former French colony, is seen as a stable democracy with an unbroken series of elections since independence in 1960.
It remains the only West African country where the army has never seized power.
|Disclaimer: Opinions expressed here are those of the writers and do not reflect those of Peacefmonline.com. Peacefmonline.com accepts no responsibility legal or otherwise for their accuracy of content. Please report any inappropriate content to us, and we will evaluate it as a matter of priority.|