Officials with the ruling party of Zimbabwean President Robert Mugabe say they are preparing for a presidential run-off.
Zimbabwe's election commission has not released any official results from Saturday's vote, but the state-owned Herald newspaper says neither Mr. Mugabe nor opposition candidate Morgan Tsvangirai received the required 50 percent of the vote.
Independent candidate Simba Makoni was running a distant third.
An official with ZANU-PF, Deputy Information Minister Bright Matonga, says the party is confident the president will win the second round of voting.
South Africa's influential "Business Day" newspaper says Mr. Mugabe is privately considering whether to take part in any runoff.
Mr. Mugabe's party has already lost control of the nation's parliament to Tsvangirai's Movement for Democratic Change. The MDC has taken 109 seats, compared to 97 for ZANU-PF.
Mr. Mugabe has ruled Zimbabwe since it gained independence in 1980. Supporters hail him as a hero of the country's independence movement, but critics say his policies have ruined Zimbabwe's economy.
Some information for this report was provided by AFP, AP and Reuters.