UEFA are looking into 12 matches in the Europa League and three in the Champions League as part of their investigation into alleged match-fixing.
European football's governing body confirmed on Friday that the matches concerned are all early qualifying round games. On Thursday police made several arrests across Europe in connection with the alleged bribing of players and officials to fix the results of games, prosecutors in the German city of Bochum revealed.
A UEFA statement read: "UEFA has been actively involved in the investigation and has given assistance via detailed information through its Betting Fraud Detection System. This detection system monitors all UEFA competitions and European national league first and second division matches for suspicious betting patterns. The information on a number of matches was passed to the German authorities upon their request."
UEFA general secretary Gianni Infantino added: "This case proves that it is possible for a state investigative authority to work closely together with a sports governing body when it comes to corruption or match fixing, and it is gratifying to see that the Betting Fraud Detection System endorsed by the UEFA president, Michel Platini, is already bearing fruit.
"We will continue our battle against any form of corruption in European football with a mission of zero tolerance.
"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."
UEFA confirmed more information about the 15 European games concerned would be given at a later date, but revealed they are part of the UEFA list of 40 matches that have previously been quoted as being 'under suspicion'.
The majority of the games under investigation are domestic league matches in nine countries, which come under the jurisdiction of their own authorities and associations.
The match fixing and corruption allegations involved "around 200" matches, the governing body confirmed.
Peter Limacher, UEFA's head of disciplinary services, told a press conference in Germany: "This is undoubtedly the biggest fraud scandal there has ever been in European football. We are deeply shocked by the extent of the match manipulations by international gangs. We now have to do everything we can so that the referees, players and officials are brought to justice."
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