Three players' agents, a referee and a former lawyer were charged and detained in Belgium on Friday as a massive football fraud and match-fixing scandal widened.

Mogi Bayat, portrayed in the media as Belgium's most powerful sports agent, was charged with "money laundering," his lawyers said, after he appeared before a judge.

Bayat was detained pending his next hearing, as were fellow agents Dejan Veljkovic and Karim Mejjati, who were questioned this week as part of the operation targeting Belgium's football elite.

Former Anderlecht club lawyer Laurent Denis and referee Bart Vertenten were also charged and arrested overnight, according to the Belga news agency.

On Thursday, another referee, Sebastien Delferiere, was charged but was immediately released on parole.

Vertenten and Delferiere were suspended on Thursday with immediate effect by the Belgian Football Federation.

The charges against referees are part of a probe into suspected match-fixing by Veljkovic in a failed effort to save formerly top-tier KV Mechelen from relegation to the second division.

On Thursday, the judge charged five people in the match-fixing case, including the club's financial director.

Hearings before the judge were held throughout night.

At this stage, at least 17 suspects have been charged, according to French-language RTBF.

A total of 29 suspects were interrogated on Wednesday, the federal prosecutor's office said on Thursday.

Several, including former Anderlecht boss Herman Van Holsbeeck, were released without charges.

The operation led to a total of 60 police searches Wednesday, including the headquarters of leading clubs in the Belgian first division, with FC Bruges, Anderlecht, Standard Liege and Genk among them.

The huge operation took place simultaneously in Belgium and six other European countries, including France and Serbia, where an agent was arrested Thursday and awaits extradition.