An Italian prosecutor has said more than two dozen leading players should be investigated by the Tennis Integrity Unit (TIU) regarding possible links to betting rings.
Two Italians formerly in the world's top 50, Potito Starace and Daniele Bracciali, have been charged in Cremona as part of an inquiry into suspected match-fixing. Both deny charges of conspiracy to commit sports fraud.
However, prosecutor Roberto di Martino claims the names of more than 24 non-Italian players are mentioned by gamblers in internet chat logs and recordings of phone calls that his inquiry has obtained - and has called on authorities to investigate.
Speaking to the BBC and BuzzFeed, he said: "There are many signs that are not coincidences that make us understand that this is a problem regarding not just Italian tennis players but also a problem that we could say is of a worldwide nature.
"It would be possible to identify, possibly hit, many foreign players who definitely are part of this system.
"Surely if these foreign players were Italian, they would certainly have been at least questioned. They should have provided some explanations.
"Interestingly, they are not so-called second-tier tennis players, but also players of some importance.
"I do not understand why there was no real initiative by the integrity unit to establish if there was something dirty behind this."
In January, an independent review of how tennis deals with alleged corruption was announced, after the sport was rocked by match-fixing claims on the eve of the Australian Open.
The TIU told the BBC it was investigating the allegations against Starace and Bracciali, and said it "acts on all evidence" as part of "a long-standing and total commitment to eradicating betting-related corruption in the sport".