Some 20,000 loyalists came to cheer on Sassou
The credibility of Congo Brazzaville's first elections in a decade have been dealt a severe blow after the main opposition candidate said he was withdrawing from Sunday's contest.
Addressing thousands of supporters of his Union for Democracy and the Republic party, Andre Milongo said that the election result had already been fixed by incumbent President Denis Sassou Nguesso.
"Fraud is the national sport of Congo," Mr Milongo said.
Party members had been refused the right to observe the voting process, he alleged, and in some parts of the country only half the ballot papers had been printed with Mr Milongo's name on them.
Later, in an interview with BBC News Online, Mr Milongo explained that he had asked the government to delay the polls to allow such problems to be worked out.
But he did not expect a reply.
"The regime just does not want us to take part," he said.
No credible challengers
International election observers are yet to make a statement on Mr Milongo's claims, and those of other opposition leaders and supporters, who say that President Sassou has used the full resources and influence of the state to get himself reelected.
Two other candidates have also pulled out of the race recently, leaving no credible challengers to the incumbent.
Mr Milongo's withdrawal came on Friday, the last day of campaigning for only the second-ever presidential elections in Congo's history.
The only other ones, in 1992, saw defeat for Mr Sassou, the country's longtime communist dictator.
The elections and their aftermath sparked a decade-long political crisis as the president, Pascal Lissouba, the prime minister, Bernard Kolelas, and Mr Sassou himself, all vied for power, influence and control of the country's oil revenue.
On three occasions this rivalry spilled over into brutal civil war. Eventually, and with the support of the Angolan and French governments, Mr Sassou came out on top, and his opponents say he has no intention of being beaten in the polls for a second time.
His supporters however, who have energetically and noisily campaigned on his behalf, say Mr Sassou is the only man who can guarantee peace and stability in Congo.
At the same time that Mr Milongo was telling his supporters not to vote, Mr Sassou was presiding over his own final campaign rally.
Some 20,000 loyalists, all wearing t-shirts or dresses bearing his face, had come to dance, sing and cheer their man on.
A sudden downpour did not put anyone off, with Mr Sassou calling the rain 'a benediction from God' and entertaining the crowd with what looked like a victory jig.