Cameroon's interior minister Paul Atanga Nji warned on Tuesday that "scoring a goal" is not "winning the match" after an opposition leader used a football metaphor to claim victory in presidential polls.Maurice Kamto, candidate of the Movement for the Rebirth of Cameroon (MRC) party, said on Monday he "was charged with taking a penalty, I took it, and I scored", proclaiming himself victor of weekend polls. He gave no evidence for his claim.Sunday's vote, at which Kamto headed a partial opposition coalition, was marked by violence in restive anglophone regions, low turnout and difficulties staging the ballot in the conflict-torn areas."Even if you score a penalty, you don't necessarily win the match at the end," Atanga Nji told AFP, adding that Kamto's announcement was a "non-event".By law each polling station must submit its results, after verification by the Elecam electoral commission, to the Constitutional Court which is responsible for announcing the final, official tally within 15 days of the vote.But a raft of unofficial results from Cameroon's almost 25,000 polling stations have already begun to circulate on social media.* Sign up to News24's top Africa news in your inbox: SUBSCRIBE TO THE HELLO AFRICA NEWSLETTERFOLLOW News24 Africa on Twitter and FacebookAhead of the polls at which 85-year-old President Paul Biya sought a seventh term, Kamto warned he would "not accept any" result tainted by fraud.The government has called Kamto an "outlaw" for announcing his own result."I have received a clear mandate from the people and I intend to defend it until the end," he said at a media briefing in Yaounde Monday.But Atanga Nji accused Kamto of creating "an unacceptable mess"."He says he'll go all the way, but he won't even have time to get going... and no one will follow him," he said.The candidate of the main opposition Social Democratic Front (SDF) party, Joshua Osih, said Monday it was "a bit premature to be giving results" and called on his seven fellow candidates to "respect the law".The United States embassy in Yaounde 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.Kamto, a former junior justice minister, was backed by rival candidate Akere Muna just before polling day, creating the first opposition electoral union since 1992.