FIFA has banned Real Madrid and Atletico Madrid from registering new signings for the next two transfer windows for breaching its rules on the international transfer and registration of players aged under 18.

The ban does not affect the current registration period and does not prevent players leaving either club, but means that after this month's transfer window closes neither Real or Atletico will be able to register any new players until the summer of 2017.

Atletico have also been hit with a €820,000 while Real have been fined €328,000.

A FIFA statement read: "The two clubs were found to have violated several provisions concerning the international transfer and first registration of minor players as well as other relevant provisions with regard to the registration and participation of certain players in competitions."

It added that "both clubs have been issued with a reprimand and given 90 days in which to regularise the situation of all minor players concerned."

Thursday's announcement comes after FIFA punished Barcelona with a year-long ban in April 2014 for the transfer of players under the age of 18.

Barca appealed to both FIFA and the Court of Arbitration for Sport against the ruling but ultimately lost both bids. However, with the ban being suspended while the appeals were ongoing Barca were able to sign six players, including Luis Suarez, in the summer of 2014.

The Catalan club eventually served their punishment during the two transfer windows in 2015, but they were still able to sign Arda Turan and Aleix Vidal from Atletico Madrid and Sevilla respectively for a combined fee of £37million last summer.

Barca were not able to register Turan and Vidal as players until this month, though, and the duo have only recently been able to make their debuts for the club.

Atletico have already announced they intend to appeal against FIFA's punishment.

A club statement read: "Our club is not in agreement with the sanction from international football's governing body and will study all the documentation we've received to present an appeal against the sanction."

Real have also confirmed they will appeal against the sanction, which they described in a statement as "absolutely unfair".

The club also announced there will be a press conference at the Bernabeu at 1930 (local time) on Thursday evening with director general Jose Angel Sanchez and Javier Lopez Farre, the director of legal services.

Oh, fuck.