Seventeen people have been arrested in Germany and Switzerland as part of an investigation into a match-fixing scandal that a Uefa official has called the biggest in European football.

German prosecutors investigating about 200 games in Europe — including at least three in the Champions League and 12 in the Europa League — ordered more than 50 police raids in Germany, Switzerland, Austria and the United Kingdom on Thursday, leading to the arrests. The matches under investigation were played in Germany, Belgium, Switzerland, Croatia, Slovenia, Turkey, Hungary, Bosnia-Herzegovina and Austria. None was played in the UK.

All the matches under suspicion are believed to have taken place this year, although neither Uefa nor the German authorities was prepared to specify if they were qualifying games or group-stage matches.

Prosecutors believe that a criminal gang has bribed players, coaches, referees and officials to fix games and made money by betting on the results.

Peter Limacher, the Uefa head of disciplinary services, said that he believed it was European football’s biggest match-fixing scandal, but stressed that the arrests provided evidence that the detection system is working.

“We at Uefa are stunned by the magnitude of this,” Limacher said. “We feel a certain satisfaction, but we are deeply affected by the scope of game manipulations by international gangs.”

In a statement, Gianni Infantino, the general secretary of Uefa, said that the body 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,” Infantino said.

German police confirmed that officers in the UK had been helping in the inquiry. The Metropolitan Police said that they had carried out a search in the Greater London area after a request from German law enforcement officials.