FIFA has confirmed an unspecified investigation into Manchester City is "ongoing".
The reasons for the probe are unclear with the world governing body giving no further details and City denying all knowledge of it.
The club say they have had no contact from FIFA concerning any new issues.
FIFA cleared City of acting inappropriately over the signing of Benjamin Garre from Argentinian club Velez Sarsfield days after his 16th birthday last year.
That case remains active, however, with Velez having appealed against the decision to the Court of Arbitration for Sport. A hearing was scheduled for July but a verdict has not yet been delivered.
When asked by Press Association Sport, FIFA would not say if these matters were linked.
A spokesperson said: "We can confirm that an investigation is ongoing in relation to the club you mention, however please note that we cannot provide any details concerning the matters under investigation."
The matter has come to light following confirmation from FIFA on Wednesday that Chelsea were being investigated over their recruitment of youth players.
City are currently banned from signing certain academy players from English clubs after being found guilty of breaching Premier League youth development rules over the signing of two players.
The ban was for two years but the second year, due to begin on June 30, 2018, will be suspended for three years.