The African Union on Wednesday called for "maximum restraint" in Cameroon following an opposition candidate's declaration of victory following the weekend's presidential vote.Ahead of the official results, Maurice Kamto, a leading opposition challenger with the MRC - the Movement for the Rebirth of Cameroon, declared himself winner of the Sunday elections.Kamto's dramatic announcement came a day after the vote which was marred by violence in restive anglophone regions, a low turnout and problems staging the ballot in the conflict-hit areas.With tensions running high over the vote, African Union Commission chairperson Moussa Faki Mahamat called for both sides to avoid aggravating the situation. "The Chairperson underlines the need for all political stakeholders to exercise maximum restraint and refrain from any statement or action that could heighten tensions," Faki said in a statement, indicating he was "closely following" developments. "Any claim relating to the electoral process should be handled through the existing legal mechanisms."Cameroonian government officials have dismissed Kamto's remarks as a "non-event," with one minister labelling him an "outlaw".By law, each polling station must submit its results for verification to the Elecam electoral commission and then to the Constitutional Court which is responsible for announcing the final tally within 15 days of the vote in which 85-year-old President Paul Biya sought reelection. But a raft of unofficial results from Cameroon's nearly 25 000 polling stations have already begun circulating on social media.On Monday, Joshua Osih, candidate for the main opposition Social Democratic Front (SDF) party, had said it was "a bit premature to be giving results" and called on his seven fellow candidates to "respect the law".And the US embassy in Yaounde also called "on all parties to wait until the official results are announced before making pronouncements about the supposed winner," in a post on its verified Facebook account.* Sign up to News24's top Africa news in your inbox: SUBSCRIBE TO THE HELLO AFRICA NEWSLETTERFOLLOW News24 Africa on Twitter and Facebook.