The campaign of Egyptian presidential candidate Ahmed Shafiq on Monday angrily dismissed claims of victory by his rival Mohammed Mursi, accusing the Muslim Brotherhood candidate of using false figures.
"It's a stolen victory because you can't claim to have won a presidential election while the polling stations are still closing," Shafiq campaign manager Ahmed Sarhan told reporters.
"It's an act of piracy to claim victory using totally false figures," he said.
"It's a false victory," added Sarhan, saying that preliminary results obtained by the campaign showed Shafiq "still ahead in the vote, with between 51 and 52 percent."
"To our mind, Mursi made this quick announcement so as to be able to claim fraud once the official presidential results are announced," he added.
Earlier, Shafiq campaign official Mahmud Baraka denounced the Brotherhood for claiming an early victory.
"We reject it completely," he told reporters. "We are astonished by this bizarre behaviour which amounts to a hijacking of the election results."
The Muslim Brotherhood claimed victory in the key presidential vote, the first since Egypt's 2011 uprising, in the early hours of Monday morning, saying Mursi led Shafiq with 52 percent of the vote after all ballot papers were counted.
Official results are not expected until Thursday, but the Brotherhood mobilised its formidable network of observers to transmit formal counts as they were tabulated at Egypt's 13,000 polling stations throughout the night.
Figures reported by local media, including state television, also put Mursi ahead of Shafiq, and the Brotherhood candidate's supporters have already hailed him as the country's first democratically elected president.
Mursi faced Shafiq in a highly polarised poll, dividing those who feared a return to the old regime with Shafiq -- the last premier under ousted president Hosni Mubarak -- from those who fear the mixing of religion and politics.