European Union sports ministers and European sports authorities meeting in Cyprus called for "effective and sustained action" to stamp out game-fixing but acknowledged that finding proof that players deliberately made mistakes or underperformed isn't easy.

"This is the biggest threat to the integrity of sports today," said Androulla Vassiliou, the European Union commissioner responsible for sports. "If we do not protect it, the soul of sport will be destroyed."

The problem of match-fixing has escalated with the advent of online betting and is not limited to soccer. But prosecuting game-fixing cases is tricky.

"When an early warning system shows high probability that a match was fixed, it may often not be accepted as material evidence for a prosecution," a report by EU-commissioned consultants KEA said.