Last updated on .From the section Snooker

World Snooker boss Barry Hearn has asked Ronnie O'Sullivan to explain his comments after the world champion said Stephen Lee is not the only player guilty of match-fixing.

Lee, 38, is awaiting sentence after a tribunal decided he had fixed seven games in 2008 and 2009.

"I've heard there's many more players who throw snooker matches," five-time world champion O'Sullivan tweeted. external-link

Ronnie O'Sullivan factfile Born: 5 December 1975

Made his first century break aged 10

Turned professional aged 16

Became youngest winner of a ranking tournament aged 17 at the 1993 UK Championship

Won first world title in 2001, beating John Higgins

Won world titles in 2004 and 2008

Won 2012 world title but on 6 November 2012 announced he was taking a break from the sport

On 23 February 2013 announced return

Won his fifth world title on May 6

Hearn called the allegations "wholly unacceptable and extremely damaging".

In a statement, external-link Hearn added: "If he has names and he knows of incidences, he has an obligation and a duty to report them and failure to do so will put him in breach of his player's contract.

"We take these type of allegations very seriously. We have written to Ronnie asking him to explain his comments and to provide details of any match-fixing and the names of the players that he is referring to."

O'Sullivan later added he had "no concrete evidence of match fixing in snooker," but hinted players were aware of who might be involved.

In the full verdict on Lee, delivered on Monday, there was no suggestion that any other player had colluded with the former world number five's corruption.

O'Sullivan, 37, added: "I suppose Steve Lee was just caught out.

"No need to worry if you got nothing to hide. But plenty of people have got loads to hide. That's why there is no free speech. They're hiding.

"They will prob (sic) fine me for talking about it. They don't like you doing that. Like to keep things under the carpet."

Judd Trump backs life bans for match fixers

Lee denied the allegations but a tribunal adjudged that he deliberately lost games against Ken Doherty and Marco Fu at the 2008 Malta Cup.

He was also found guilty of agreeing to lose the first frame against both Stephen Hendry and Mark King at the 2008 UK Championship and throw matches by a pre-determined score to Neil Robertson at the 2008 Malta Cup and to Mark Selby at the 2009 China Open.

He similarly conspired to lose his 2009 World Championship first-round match to Ryan Day, going on to be defeated 10-4.