He emerged on the eve of the election to announce he would vote for the opposition, surprising Mnangagwa who accused him of striking a deal with Chamisa.
Mugabe made no comment to reporters as he cast his ballot around lunchtime accompanied by his wife, Grace. A huge crowd gathered outside, some cheering, many booing.
Mnangagwa, a former intelligence chief, denied Mugabe’s claim that the vote would not be free since it was being run by a “military government”.
“I can assure you that this country is enjoying democratic space which has never been experienced before,” Mnangagwa told public television after voting.
Mnangagwa, of the Zimbabwe African National Union-Patriotic Front (ZANU–PF), has been President since the military ousted Mugabe in a bloodless coup.
Elections under Mugabe were often marred by intimidation, rigging and violence but the consensus is the build-up to this vote has been better than before, although Chamisa complained about a flawed voters’ roll and opaque ballot paper printing.
“Victory is certain, the people have spoken,” Chamisa said after casting his ballot in Harare as a cheering crowd chanted: “President! President! The president is here!”
“I have no doubt that by end of day today we should be very clear as to an emphatic voice for change.”
Chamisa has attracted young and unemployed voters frustrated with nearly four decades of ZANU–PF rule.
“I’ll vote for Chamisa because it is a vote for change, it is a vote for the youth. Tomorrow we will have a new president,” said Fabian Matsika, a security guard in Harare.
“ZANU-PF is the only party that I have voted for,” said Elizabeth Kamhunga, 67, after casting her vote in Harare. “We may have made some mistakes but I think President Mnangagwa is the only person who has the interests of Zimbabwe at heart.”
The European Union, the United States and the Commonwealth have sent observers.
“It is exciting to see so many Zimbabweans casting ballots,” said former Liberian president Ellen Johnson Sirleaf, co-leader of the National Democratic Institute’s observer mission.
“However the public’s faith in the secrecy of the ballot is essential for the credibility of the process. We urge the authorities to do everything possible to ensure the secrecy of today’s vote.”
Mnangagwa has made a big effort to win over foreign opinion; hosting Western ambassadors, courting investors and patching up relations with white commercial farmers who were violently evicted from their farms under Mugabe.- Reuters
Robert Mugabe casts his vote