Manchester City has been guilty of breaking the rules on international transfer and registration of players aged younger than 18, FIFA said on Tuesday.

The Premier League champions could have faced a transfer ban, but instead FIFA’s disciplinary committee fined City 370,000 Swiss francs (US$389,711).

The punishment “took into account the fact that Manchester City FC accepted its responsibility,” FIFA said in a statement.

While confirming that they were willing to accept the fine, City claimed the problems occurred before FIFA clarified the rules.

The club said in a statement that the fine concerned “the international transfer of players under the age of 18, particularly in relation to their trial periods and participation in friendly games.”

“The club accepts responsibility for the breaches which arose as a result of misinterpretation of the regulations in question. All of the breaches occurred before December 2016, when guidance on the interpretation of the provisions was issued, since which date Manchester City has been fully compliant,” it added.

Last year, FIFA cleared City of any wrongdoing over their 2016 signing of Benjamin Garre from Velez Sarsfield just after the Argentine midfielder’s 16th birthday.

Also last year, two players from the Right to Dream soccer academy in Ghana, Sierra Leone’s George Davies and Ghana’s Dominic Oduro, told Danish newspaper Jyllands-Posten that they signed for City and played in youth matches before they turned 18.

Both spent two years at the club. Davies last played for Riga FC and Oduro now plays for the Tampa Bay Rowdies in the US.

City are also being investigated by the Premier League, England’s Football Association and UEFA, the governing body of European soccer.