Zimbabwe's opposition says its candidate, Nelson Chamisa, has won Monday's presidential election.
The MDC Alliance says the ruling Zanu-PF party is attempting to rig the vote to allow President Emmerson Mnangagwa to win, and the delay in releasing official results is unacceptable.
The electoral commission has said there has been no cheating and it needed time to collate the votes.
The polls were the first since long-serving ruler Robert Mugabe was ousted.
The vote attracted a high turnout of 70% and was monitored by international observers.
Speaking at a press conference in the capital, Harare, the MDC Alliance's Tendai Biti said there was a clear attempt by Zanu-PF to interfere "with the people's will".
He warned the party not to "plunge Zimbabwe into chaos".
More than 5.6 million people were registered to vote
The opposition announcement pre-empted official results.
A Zanu-PF spokesman told the BBC he had "no clue" what Mr Biti was talking about.
The party, which has been in power since independence in 1980, has been accused of rigging previous elections to keep Mr Mugabe in office.
What's been the reaction on the streets?
There have been celebratory scenes outside the MDC Alliance headquarters in Harare.
Crowds have been singing and dancing since Mr Biti said that Mr Chamisa had won.
A truckload of policemen and water cannons also drove near the building in an apparent show of force.
However, many businesses reopened on Tuesday after being shut on voting day, a public holiday.
When will we know the official winner?
The Zimbabwe Electoral Commission (Zec) has until Saturday to announce the results but its chairwoman, Priscilla Chigumba, said she expects the announcement to be made well within that deadline.
"We will not subvert [the people's will]," she said at a press conference, rejecting allegations that there was rigging.
Observers say the race between Mr Mnangagwa's Zanu-PF party and Mr Chamisa's MDC Alliance is extremely tight.
Both men are among 23 candidates running for president.
Zec has announced some of the results in the parliamentary elections but says it needs time to pull together the figures for the presidential poll from across the country.
A presidential candidate needs more than 50% of the vote to win outright. Otherwise, a run-off election will be held on 8 September.
In a tweet, Mr Mnangagwa expressed confidence about his chances but added that he was "waiting patiently for official results as per the constitution".
'Anxiety creeps in'
By Pumza Fihlani, BBC News, Harare
The electoral commission held two press conferences on Tuesday in a bid to keep the public informed.
But it is the result of the presidential election that people want to know and that will not be ready for another few days.
There were more than 10,000 polling stations and collating the votes will not be an easy task.
In the meantime, accusations are surfacing and anxieties are starting to creep in.
On the sidelines of the jostling of the politicians, the fake news media machine has kicked into full gear, with social media accounts, purporting to belong to politicians, claiming victory for their parties.
While the voting process was peaceful the waiting and any perceived delays could raise the temperature here.
The commission has told South Africa's public broadcaster that it is under no "political pressure", implying that it will not be rushed.
But in the age of social media, where false stories thrive in an information vacuum, it does raise questions about how democracies can respect the electoral process without creating room for the very credibility of that process to be jeopardised.
Latest Stories
-
Ghanaian Sakafia Islamic SHS wins the 2025 Zayed Sustainability Prize
11 minutes -
Pack of ‘hungry’ dogs kill Nigerian woman in Italy
25 minutes -
From the Pitch to the Studio: Joseph Painstil’s Musical Journey
1 hour -
Apaak reaffirms commitment to free tuition for first-year tertiary students
1 hour -
NDC’s free tuition for first-year university students won’t be compulsory – Clement Apaak
1 hour -
ORAL receives over 700 petitions; preparing to submit report to Mahama
1 hour -
Today’s front pages :Thursday, January 16,2025
1 hour -
GIBA seeks mandatory injunction to stop the Ministry of Communications and Digitalization and KNet Ghana Ltd from illegal fee demands
2 hours -
Nsoatreman Coach Yaw Preko awaits Fate after fan invasion at training grounds
2 hours -
NPP is no longer strong, says Sammy Crabbe
2 hours -
‘We’re not inviting anyone, just collecting data’ – Domelevo on ORAL criticism
2 hours -
Dubik Mahama rejects proposal for further privatisation of ECG
3 hours -
Joynews’ Ohemeng Tawiah sustains life-threatening injuries in police-illegal miners clash
3 hours -
Residents of Nungua demand intensified police patrol due to rise in robberies
3 hours -
Government urged to keep investing in technical, vocational education
3 hours