Atletico Madrid have lodged an appeal against their two-window ban on registering new players with FIFA.
On January 14, Atletico and Real Madrid were handed sanctions by the governing body's Disciplinary Committee as a consequence of breaches "relating to the international transfer and registration of players under the age of 18".
The punishment prohibits the club from registering new players in the next two transfer windows and included a fine of 900,000 Swiss francs.
After studying the documentation, Atletico have notified the FIFA Appeal Committee of their desire to contest the punishment.
The club have maintained their innocence and have requested the ban be suspended until a decision on the appeal is reached.
A statement read: "We consider that we have acted within the law in all cases. In addition, we request the probationary suspension of the sanction pending the outcome of the appeal."
Real Madrid have confirmed their intention to appeal, but are yet to announce that their challenge has been formally submitted.
Barcelona received a similar punishment in April 2014, although an unsuccessful appeals process meant the sanctions did not take effect until January 2015 and the following off-season's window.
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