The Zimbabwe Electoral Commission (ZEC) is starting to announce results of the first election since the end of Robert Mugabe's nearly four decade rule.
Zimbabwe's President Emmerson Mnangagwa and his main opponent Nelson Chamisa both said on Tuesday they were confident of victory.
Mnangagwa, 75, a long-serving security chief who took power after Mugabe was toppled in a de facto coup in November, said he was receiving "extremely positive" information on the vote. Chamisa, 40, said his opposition Movement for Democratic Change (MDC) had done "exceedingly well".
Western diplomats and local observer groups said the race, which saw a turnout of 75 percent, was too close to call.
The final outcome may not be known until August 4.
As well as electing a president, Zimbabweans were voting for 210 members of parliament and more than 9,000 councillors.