Chelsea is under investigation by FIFA for a third time in eight years over the signing of foreign players under the age of 18.

Chelsea have said they comply with “all FIFA statutes and regulations when recruiting players” but the world governing body has been alerted to alleged impropriety and says it is looking into it.

“We can confirm that an investigation is ongoing,” Fifa said in a statement. “We cannot provide any details concerning the matters under investigation.”

Atletico Madrid are currently under a transfer ban for signing youth players while Real Madrid recently had a ban as well.