All seven opposition leaders who contested Guinea's presidential election against incumbent Alpha Conde said on Monday the result should be annulled because of fraud.
Their declaration is likely to stoke tension in the West African country, which has a history of political violence, including at the 2010 election that brought Conde to power.
Conde, who rose to power in a military coup, is favored to win a second term, although the result from Sunday's vote may be close enough to require a second round. Early results announced by radio stations so far showed Conde in the lead.
The opposition candidates, including the main opposition leader, Cellou Dalein Diallo, told a news conference that there were numerous examples of fraud in the election.
Diallo said voters registered this year in the city of Labe in central Guinea received no voting cards and only those who voted in 2010 could cast their ballots on Sunday.
"The election was a masquerade which started yesterday and still continues today at the central (election) commission level. In these conditions, we again demand that the election be scrapped because we cannot recognize results issued through this process," Diallo said.