About 200 European football games are under investigation in a match-fixing inquiry, German prosecutors have said. At least three of the games were in the Champions League and another 12 were in the Uefa Europa League, officials said. Uefa representative Peter Limacher called it the biggest match-fixing scandal ever to hit Europe. On Thursday police carried out about 50 raids in Germany, the UK, Switzerland and Austria, making 17 arrests and seizing cash and property. Fifteen of those arrested were in Germany and the other two in Switzerland. Matches under investigation were played in Germany, Belgium, Switzerland, Croatia, Slovenia, Turkey, Hungary, Bosnia-Hercegovina and Austria. Officials said the games included the 40 which Uefa revealed in September were under investigation. 'Stunned' Prosecutors believe a 200-strong criminal gang has bribed players, coaches, referees and officials to fix games and then made money by betting on the results. The investigation is being carried out by German authorities and supported by Uefa, the European football body. " Uefa will be demanding the harshest of sanctions before the competent courts for any individuals, clubs or officials who are implicated in this malpractice " Gianni Infantino, Uefa general secretary All the matches under suspicion are believed to have taken place this year, although prosecutors did not specify if they were qualifying games or group-round matches. Speaking at a news conference in Germany, Mr Limacher said the revelations represented "clearly" the worst ever match-fixing scandal in European football. "We at Uefa are stunned by the magnitude of this," he said. On the positive side, he said the arrests were proof that the detection system was working. MATCHES UNDER INVESTIGATION Champions League: 3 Europa League: 12 Germany: 32 (second division or lower) Belgium: 17 (second division) Switzerland: 22 (second division) Croatia: 14 (first division) Slovenia: 7 (first division) Turkey: 29 (first division) Hungary: 13 (first division) Bosnia: 8 (first division) Austria: 11 (first division or lower) Under-21 European Championship: Unspecified Source: German police "We feel a certain satisfaction, but on the other side we are deeply affected by the scope of game manipulations by international gangs," he added. In a statement Uefa's general secretary, Gianni Infantino, said it would continue to impose "zero tolerance" on any form of corruption in European football. "Uefa will be demanding the harshest of sanctions before the competent courts for any individuals, clubs or officials who are implicated in this malpractice, be it under state or sports jurisdiction," he said. A German police spokesman told the BBC that officers in the UK had been helping in the inquiry but that no British football matches were under suspicion. UK police said they had carried out a search in the Greater London area following a request from German law enforcement officials. Detection system Earlier this year Uefa President Michel Platini described match-fixing as the "greatest danger to football". In 2006, Italian clubs Juventus, Fiorentina, Lazio and AC Milan were all found guilty in a match-fixing inquiry. Juventus were relegated while Fiorentina, Lazio and AC Milan had points deducted. German football was rocked by a match-fixing scandal in 2005 when referee Robert Hoyzer confessed to trying to manipulate games in the second division, third division and German Cup. His testimony revealed a network of corruption linked to a Croatian gambling syndicate. Uefa has since introduced an early warning system which flags up unusual betting patterns. The betting fraud detection system monitors real-time betting, giving investigators an immediate idea of whether there are irregular patterns. The recent arrests would seem to indicate the detection process is working, but the scale of the manipulation must be a concern, says BBC Sports reporter Alex Capstick.