Senegal is to hold a second round of presidential elections after incumbent Abdoulaye Wade failed to win outright, election officials have confirmed.
Mr Wade gained 34.8% of the vote in Sunday's first round.
He faces a run-off next month against his former prime minister, Macky Sall, who came second with 26.5%.
Mr Sall urged the opposition to rally behind him against Mr Wade, who has been in power since 2000 and is seeking a controversial third term.
"I'm sure the desire for change of the Senegalese people will give me the victory in the second round," Mr Sall said at a press conference after the results were announced.
Two other ex-prime ministers took third and fourth place: Moustapha Niasse with 13.2% and Idrissa Seck with 7.8%.
Mr Niasse has already urged his supporters not to support Mr Wade, but has so far not officially endorsed Mr Sall.
He belongs to the opposition grouping, June 23 Movement (M23), which has campaigned against Mr Wade's third term bid.
"The M23 message is that Wade must get out. The fundamental objective is that Wade's third term mandate does not happen," AFP news agency quotes M23 co-ordinator Alioune Tine as saying in Senegal's Quotidien newspaper.
Mr Sall promised that if elected, he would shorten the presidential term to five years from the current seven, and enforce a two-term limit.
He also promised to bring in measures to reduce the price of basic foodstuffs.
Analysts say Mr Wade, who faced 13 challengers in the first round, is likely to struggle in the run-off.
His bid for a third consecutive term has sparked weeks of violent protests in recent months, leading to about six deaths, although polling on Sunday was largely peaceful.
The second round is scheduled for 18 March.
On Tuesday, Mr Wade's admitted he had failed to win more than 50% in the first round.
He also said that he would be opening talks with opposition candidates ahead of the run-off.
The president was booed as he cast his vote on Sunday in the capital, Dakar - and he lost in his own constituency.
Senegal's constitutional court ruled in January 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.
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.