FIFA has opened an investigation into Chelsea's transfer dealings amid suggestions that the Premier League leaders have breached regulations concerning the recruitment of youth players.
The Daily Mail reported on Tuesday that FIFA had launched an inquiry into Chelsea's conduct when recruiting foreign players under the age of 18.
Contacted by ESPN FC, FIFA said: "We can confirm that an investigation is ongoing, but we cannot provide any details concerning the matters under investigation."
Chelsea were hit with a transfer ban in 2009 -- lifted after a successful appeal to the Court of Arbitration for Sport (CAS) -- relating to the 2007 signing of Gael Kakuta from Lens, while FIFA last year also investigated Bertrand Traore's move to Stamford Bridge, though no action was taken.
Responding to the news of the FIFA probe, a Chelsea spokesman said: "Chelsea FC complies with all FIFA Statutes and Regulations when recruiting players."
Barcelona and Real Madrid have both received transfer bans after being found guilty of violating FIFA rules on signing foreign minors, while Atletico Madrid are unable to register new players until January 2018 after their appeal against a similar charge was dismissed by CAS.
Chelsea's case is not reported to be as serious as any of the Spanish giants, though FIFA reserves the right to hand down sanctions ranging from a fine to a transfer ban if the Blues are found to have acted improperly.