ZURICH, Switzerland — Spanish giants Real Madrid suffered another institutional embarrassment yesterday as they and rivals Atletico Madrid were banned by FIFA from buying players for one year over their dealing in under-age players.

The ban will start from the July transfer window this year and finish with the January transfer market in 2017 meaning newly appointed Real coach Zinedine Zidane will be unable to strengthen his squad this summer.

Atletico were also fined 900,000 Swiss francs (820,000 euros) and Real 360,000 (330,000 euros). However, both clubs are still allowed to sign players until the end of the month.

“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,” said a FIFA statement.

Atletico announced they will appeal, whilst Real made no immediate comment.

“We will appeal, we think we are right and I think this is unjust,” said Atletico president Enrique Cerezo.

“Not being able to sign is a problem because the seasons are very long and you always need players. Fortunately, we have a good and big squad with young players that can overcome these two windows without signings.”

European champions Barcelona have just completed a one-year ban for similar reasons.

Barca were initially banned in April 2014, but managed to delay the sanction taking effect until the transfer windows in January and the summer of 2015 by launching an ultimately unsuccessful appeal to the Court of Arbitration for Sport (CAS).

By delaying the ban, Barca managed to sign the likes of Luis Suarez and Ivan Rakitic in the summer of 2014 to propel them to a treble of La Liga, Champions League and Copa del Rey, a route potentially open to both clubs depending on how quickly CAS could hear any potential appeal.

Real and Atletico were “issued with a reprimand and given 90 days in which to regularise the situation of all minor players concerned,” FIFA said. They can still sell players during the transfer ban.

FIFA said the alarm was raised over the two clubs by FIFA’s Transfer Matching System and its disciplinary committee completed the inquiry.

Under international football rules, players under 18 cannot be transferred to another country, except in limited circumstances. All transfers need the approval of a special FIFA committee.