HARARE, Zimbabwe (AP) — There is tight security in Zimbabwe's capital Wednesday as the Constitutional Court is set to hear the main opposition party's challenge to the results of last month's historic presidential election.

Police have barricaded the roads around the court in central Harare as tensions have risen ahead of the crucial court case which will decide if the election of President Emmerson Mnangagwa is valid.

The opposition claims the vote had "gross mathematical errors" and it seeks a fresh election or a declaration that its candidate Nelson Chamisa is the winner of the July 30 vote.

The Zimbabwe Electoral Commission declared Mnangagwa narrowly won with 50.8 percent of the vote, avoiding a runoff. Chamisa received 44.3 percent, said the commission.

The election was the first after the fall of longtime leader Robert Mugabe. Many hoped the peaceful vote would launch a new era for Zimbabwe but two days later six people were killed when the military swept into the capital to disperse opposition protesters.

Western election observers and diplomats condemned the "excessive" use of force.

Chamisa's challenge claims the electoral commission bumped up Mnangagwa's figures through double counts and the creation of "ghost" polling stations. It also alleges that some polling stations recorded more voters than those registered to vote.

Mnangagwa and the electoral commission argue the application should be dismissed on a technicality, because it was filed too late and that papers were not properly served on respondents.

In his affidavit, Mnangagwa argues the court should not hear Chamisa'a application because he "scandalized" the court by claiming during political rallies that the judiciary was biased toward the ruling party, ZANU-PF. Mnangagwa accuses Chamisa of making "illusionary promises" to voters during campaign.

The case will be televised live by the state broadcaster, the Zimbabwe Broadcasting Corporation, but the courts have ruled that the proceedings cannot be livestreamed on social media. Journalists and other people accredited by the court will follow proceedings from a giant television screen on the court premises, but they are not permitted to carry mobile phones or laptops, preventing them from filing during the case.

This is not the first time the opposition has challenged election results in court. Following the 2013 presidential election, then main opposition leader Morgan Tsvangirai filed a challenge before the court. He later withdrew the challenge claiming he would not get a fair hearing. The court declined his withdrawal and proceeded to rule on the case on favor of Mugabe.

According to Veritas, a legal think tank based in Harare, the court can declare a winner or invalidate the election and call for a fresh election or make any other order it considers "just and appropriate."

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