Zimbabwe’s main opposition leader on Sunday alleged “blatant and gigantic fraud” in the country’s election after President Emmerson Mnangagwa was declared the winner and international observers reported an atmosphere of intimidation against voters.

The returns from the latest troubled vote in the southern African nation were announced Saturday night, two days earlier than expected. Opposition leader Nelson Chamisa’s Citizens Coalition for Change party said it would challenge the results as “hastily assembled without proper verification.”