Zimbabwe’s main opposition is claiming that voting results forms were not posted at more than one-fifth of the country’s polling stations as the law requires.
The opposition says results it has collected from around the country show “beyond a reasonable doubt” that Nelson Chamisa has won the presidential election.
It says 21% of forms were not posted at stations.
Zimbabwe’s electoral commission is expected to release the first results of Monday’s vote shortly.
The election was the first since longtime leader Robert Mugabe stepped down in November under military pressure and former confidante Emmerson Mnangagwa took power.
Mnangagwa also has expressed optimism about the results.