A top member of Mugabe's ZANU-PF party told AFP that Mugabe had trounced Morgan Tsvangirai and his Movement for Democratic Change in Wednesday's presidential and parliamentary elections.
"We have romped (to victory) in a very emphatic manner," said the party member who asked not to be named. "We have won all of them, including the presidential and parliamentary."
But the claim was swiftly slapped down by Tsvangirai, bidding for a third time to end 89-year-old Mugabe's 33-year rule of the troubled southern African country.
"In our view this election is null and void," he added. "This election has been a huge farce."
More From This Section
"The shoddy manner in which it has been conducted and the consequent illegitimacy of the result will plunge this country into a serious crisis."
The Zimbabwe Electoral Commission said the count has been completed and results are now being collated from the first vote since bloody polls in 2008 led to an uneasy power-sharing deal between Tsvangirai and Mugabe.
Tsvangirai stopped short of claiming victory himself, a move that could have enflamed tensions in a country where political violence is common.
Foreign diplomats and independent Zimbabwean election observers also expressed grave misgivings about the conduct of the poll.
"Up to a million voters were disenfranchised," said Solomon Zwana the chairman of Zimbabwe Election Support Network, which has 7,000 observers. "The election is seriously compromised."
The Catholic Church -- which has 3,000 people on the ground -- said it was premature to call a winner but there was a "strong feeling" across the country that Mugabe would lose.