Mugabe's remarks came as the Movement for Democratic Change -- the party of Prime Minister and presidential candidate Morgan Tsvangirai -- accused the president's Zanu-PF party of tampering with voters' rolls.
The BBC said Tuesday the rolls include the names of thousands of dead people, with some names appearing several times with variations in their identification numbers or home addresses.
Zanu-PF denied the accusation, saying it was the responsibility of the electoral commission, which only released the roll of voters on the eve of Wednesday's election.
Mugabe and Tsvangirai are longtime rivals who have shared power in Zimbabwe since 2009 in a deal brokered to end conflicts which marred elections in 2008.
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