The hacker group Fancy Bears has published a list of players who were allegedly allowed to use banned substances at the 2010 World Cup in South Africa.
Argentina's Diego Milito, Carlos Tevez, Juan Sebastian Veron and Gabriel Heinze are among the 25 footballers who, according to the leaked document, were granted Therapeutic Use Exemptions (TUEs) during the tournament.
Netherlands forward Dirk Kuyt and Germany striker Mario Gomez are also named on the list, which details substances that certain players were granted permission to use for medical reasons.
There is no suggestion in the leaked document that any of the players named had breached anti-doping regulations.
The list was published as part of a Fancy Bears release that includes claims that 160 unnamed footballers failed doping tests in 2015.
The group has revealed what it says is a document from the World Anti-Doping Agency (WADA) that details examinations carried out across world football.
In a statement posted via their website accompanying the documents, Fancy Bears said: "Greetings citizens of the world.
"You can have a look at WADA documents revealing that more than 150 players were caught doping in 2015. The next year this number increased up to 200 athletes.
"Today Fancy Bears' hack team is publishing the material leaked from various sources related to football. Football players and officials unanimously affirm that this kind of sport is free of doping. Our team perceived these numerous claims as a challenge and now we will prove they are lying."
It is the first time the group has released information that it claims pertains to doping in football, having previously focused on the medical records of athletes.
Omnisport has contacted FIFA and WADA for comment.
