The runner-up in Democratic Republic of Congo's presidential election says he in fact won a landslide victory with more than 60 per cent of votes and will file a formal fraud complaint.
The vote was intended as Congo's first democratic transfer of power in six decades, but instead threatens to reawaken violence in the huge and tumultuous nation where millions have died during civil wars since the 1990s.
"When you know you are in the right, you are not allowed to remain home," Martin Fayulu said, urging supporters to "rise up" and contest the results with him.
Though pre-election polls predicted a landslide for Fayulu, a businessman and former manager at Exxon Mobil, the national election board, CENI, said he lost to another opposition candidate, Felix Tshisekedi, 55.
Fayulu's camp said on Friday its tally showed he won 62 per cent of votes, to Tshisekedi's 19 per cent.
His supporters believe authorities rigged the result in a deal to protect members of President Joseph Kabila's outgoing administration and maintain his influence over security forces.
The influential Catholic Church has also rejected the official result based on tallies by its bishops conference's (CENCO) 40,000-strong observer mission. France and former colonial power Belgium also expressed doubts.
In comments to the UN Security Council via teleconference on Friday, CENI president Corneille Nangaa defended the vote's credibility and attacked CENCO.
"I'd be very interested to know what party they work for," said Nangaa. "I challenge anyone to say they have the pretension to have collected all the vote tallies."
CENCO president Marcel Utembi, at the same table as Nangaa at UN headquarters in Kinshasa, told the Security Council the bishops' mission was independent and its conclusions were based on tally sheets representing 72 per cent of ballots.
CENCO has not stated publicly who it believes won the election, but three diplomats briefed on its findings told Reuters it had determined Fayulu was the clear winner.
The head of the UN peacekeeping mission in Congo, Leila Zerrougui, said preliminary reports from her mission and other observers all indicated the vote "happened satisfactorily despite the technical, logistical and security problem".
Yet internal UN reports seen by Reuters noted allegations of irregularities across the country, including militia fighters reportedly forcing voters to select candidates from the ruling coalition. Another domestic observer mission said it witnessed vote tampering and other "major" irregularities.
Fayulu's camp said it would raise these issues with Congo's highest court on Saturday morning. It has asked the election board to publish results from every polling station.
"We know the Constitutional Court is composed of Kabila's people, but we do not want to give any chance to Kabila and his team to say ... you didn't follow the law," Fayulu, 62, told the BBC.
Many Congolese fear the dispute could restart a cycle of unrest in a country where wars causing hunger and disease have ravaged the population.