LONDON — As more and more players speak out about match-fixing in tennis, the sport's leaders are intent on keeping the game clean.

Top-20 player Andy Murray told the BBC on Tuesday it is easy to throw a match, and the ATP Tour immediately asked him to explain himself.

"It's difficult to prove if someone has tanked a match or not tried because they can try their best until the last couple of games of each set and then make some mistakes, a couple of double-faults, and that's it," Murray said. "It's pretty disappointing for all the players, but everyone knows it goes on."

The ATP and the International Tennis Federation are joining the WTA Tour and the Grand Slam Committee to come up with a unified set of regulations to combat match-fixing and illegal betting.

"Tennis is vulnerable," ITF executive director Bill Babcock said. "We have to keep the integrity of the matches. I think we have that, but we have this looming cloud now that we have to dissipate."

Suspicions about match-fixing began about two months ago after an online betting site, in an unprecedented move, voided bets on a match in August between fourth-ranked Nikolay Davydenko and 87th-ranked Martin Vassallo Arguello in Poland because of irregular betting patterns. Davydenko withdrew from the match in the third set because of a foot injury, and the ATP is investigating.

"Nothing is more important than the integrity of our sport and the ATP has shown that it will act where it has information which requires investigation," the men's tour said Tuesday. "It is the responsibility of everyone, without exception, to ensure we have any information about possible threats to the integrity of tennis."

ATP president Etienne de Villiers said the group is setting up a "Tennis Integrity Unit" to look into the issue.

"We have had a number of very constructive meetings on the issue this year and will be meeting again this week, with external experts, to discuss the next steps in ensuring a unit becomes a reality as soon as possible," de Villiers said in a statement.

Babcock said the group is seeking help from sports such as horse racing and cricket.

"Experts in those sports have found a way to keep those sports clean," he said.

"It's a huge work in progress," Babcock added. "It needs to conclude with expert resources."