Real Madrid released a statement on Monday night saying they comply fully with Fifa’s rules on transfers involving under-age players.
The club also acknowledged that football’s governing body exerts rigid control over international transfers of minors and had opened an investigation into the deals involving under-age players.
Earlier, during Lucas Silva’s presentation, the club director, Emilio Butragueño, said he knew Fifa had asked the Spanish federation for documents relating to the transfers of minors to Real over the past five years.
Butragueño said: “We are in agreement with Fifa in this matter and we will continue collaborating with them in everything that is asked of us. We are absolutely calm about how Real Madrid has proceeded.”
In the statement Madrid said Fifa has asked for information about 51 players but said a majority of them were exempt from regulations for various reasons.
Among the exemptions cited by Madrid were that 10 were Spanish nationals and 23 foreign players had already been registered with a Spanish club.
On Thursday Madrid signed the 16-year-old Norwegian midfielder Martin Odegaard from the Norwegian club Stromsgodset.
Barcelona fell foul of Fifa’s rules on registering minors in February 2013 and had a transfer ban imposed that means the Catalan club cannot sign players until 2016. Fifa found that Barcelona had violated those regulations when they signed 10 players under 18 to their academy.
In December Barcelona had their appeal against the ruling dismissed by the Court of Arbitration for Sport.
Although Madrid do not have a youth academy that includes a boarding school for minors like Barcelona’s renowned La Masia, they do operate youth teams.
Spain’s federation said it had no comment.