Zimbabweans have been voting in fiercely contested presidential and parliamentary elections which have already been hit by fraud allegations.
President Robert Mugabe, 89, has said he will step down after 33 years in power if he and his Zanu-PF party lose.
Polling began on Wednesday with long queues of people braving a bout of unseasonably cold weather to stand in line from well before dawn.
It is the African country's first general election since violence at the polls in 2008 forced the main political parties into an uneasy power-sharing deal.
Some 6.4 million people are registered to vote in the presidential, parliamentary and local elections and there are more than 9600 polling stations.
Five candidates are competing in the presidential race, but incumbent Mr Mugabe and Prime Minister Morgan Tsvangirai from the Movement for Democratic Change are the front-runners, DPA reports.
If neither wins 50% of the ballots in the first round, a run-off is set for September.
It is the third attempt by 61-year-old Mr Tsvangirai to unseat Mr Mugabe, who has led Zimbabwe since independence in 1980.
The Movement for Democratic Change has already accused Zanu-PF or doctoring the electoral roll. Zanu-PF has denied this, the BBC reports.
The elections are the first to be held under the new constitution approved in a referendum in March this year. Campaigning has been peaceful, with no reports of violence or intimidation.
The government has barred Western observers from monitoring the elections, but the African Union and the Southern African Development Community, as well as local organisations, have been accredited.