A wide-ranging match-fixing investigation has uncovered more than 680 suspicious games _ including World Cup and European Championship qualifiers and two Champions League games _ and found evidence that a Singapore-based crime gang is closely involved in match-fixing, Europol said Monday.

The investigation by Europol, the European Union's joint police body, found 380 suspicious matches in Europe and another 300 questionable games outside the continent, mainly in Africa, Asia and South and Central America.

"This is a sad day for European (soccer)," Rob Wainwright, the head of Europol, told a news conference. He said criminals were cashing in on soccer corruption "on a scale and in a way that threatens the very fabric of the game."

Europol said 425 match officials, club officials, players and criminals from at least 15 countries were involved in fixing the European soccer games dating back to 2008. The agency declined to name specific suspects, teams or games so as not to disrupt ongoing national police investigations.

It was unclear exactly how many of 680 games mentioned were previously known to have been tainted, but the very public announcement shed light on the murky underworld of match-fixers, who bet on fixed games to reap enormous profits around the globe.

The probe uncovered (EURO)8 million ($10.9 million) in betting profits and (EURO)2 million ($2.7 million) in bribes to players and officials and has already led to several prosecutions.

Those numbers are far lower than many previous estimates of the amount of cash involved in match-fixing and betting on rigged matches, but prosecutors said the amounts they named were what they could directly pin down through 13,000 emails, paper trails, phone records and computer records.

"This is the tip of the iceberg," said German investigator Friedhelm Althans, who also said two World Cup qualification matches in Africa and one in Central America were among those under suspicion.

Wainwright said while many fixed soccer matches were already known from criminal trials in Europe, the Europol investigation that began in July 2011 lifted the lid on the widespread involvement of organized crime in rigging games.

"This is the first time we have established substantial evidence that organized crime is now operating in the world of football," he said. "(That) highlights a big problem for the integrity of football in Europe."

He said a Singapore-based criminal network was involved in the match-fixing, spending up to (EURO)100,000 ($136,500) per match to bribe players and officials.

The global nature of the organized crime syndicates involved makes them hard to track down and prosecute. Europol said a single fixed match can involve up to 50 suspects in 10 different countries.

Europol said the criminal group behind most of the match-fixing was placing bets mainly in Asia.

"The ringleaders are of Asian origin, working closely together with European facilitators," the organization said, but it added that "Russian-speaking" and other criminal gangs were also involved.

Wainwright said the soccer world needed a "concerted effort" now to tackle the corruption. He said he would be sending the results of the investigation to UEFA President Michel Platini.

UEFA, which oversees European soccer and organizes the Champions League, seemed surprised by the breadth of Europol's accusations. It said it expected more information on the Europol investigation shortly.

"Once the details of these investigations are in UEFA's hands, then they will be reviewed by the appropriate disciplinary bodies in order that the necessary measures are taken," UEFA said in a statement.

Previous investigations have found that a World Cup qualifier between Liechtenstein and Finland in September 2009 was fixed by a referee from Bosnia, who UEFA banned for life.

Last year, UEFA expelled a Malta player implicated in fixing a European Championship qualifier between Norway and Malta in June 2007.