The entire North Korean team was targeted for testing after their match against Colombia on July 6 following the provisional suspensions Song Jong-Sun Song and Jong Pok-Sim.

And a FIFA statement today read: "As the proceedings are still in progress, FIFA will not disclose the names of the three players whose test results have produced adverse analytical findings, in accordance with the World Anti-Doping Code."

A sixth player, Colombian goalkeeper Yineth Varon, also tested positive following an out-of-competition test which was carried out before the start of the tournament on June 25.

FIFA have not identified the substance involved in any of the positive tests.