Gambian leader Yahyah Jammeh, who vowed to rule the tiny West African nation for "a billion years", was handed a shock election defeat on Friday, 22 years after seizing power in a coup.
The electoral commission head declared Adama Barrow president-elect on state television, with 45.5 percent of the vote against Jammeh's 36.7 percent.
He earlier told reporters in Banjul that Jammeh would concede, although he has yet to make a public statement.
Barrow also told Reuters by telephone on Friday that he was expecting a phone call from Jammeh conceding defeat. Defeat and a concession from Jammeh would be momentous.
Voting against Jammeh was a rare show of defiance against a leader who, human rights groups say, routinely crushes dissent by imprisoning and torturing opponents.
Gambians voted on Thursday amid a total blackout of the internet and all international calls, and with land borders sealed, in a poll posing the first serious challenge to Jammeh since he seized power in a coup in 1994.
Jammeh's supporters deny abuses and he has often criticised Western powers for meddling in African affairs.
Barrow, who has for the first time united and galvanised Gambia's opposition, has promised to revive the economy, whose sluggishness pushes thousands of Gambians to flee to Europe in search of a better life.
He has also promised to end human rights abuses and to step down after three years as a boost to democracy.
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