Barcelona was banned by FIFA from signing any new players for next season after being found guilty on Wednesday of repeatedly breaching transfer regulations.
The heavy sanction, which covers the summer and January transfer windows, followed an investigation over the past year into the Spanish champion's signing of players under the age of 18 from 2009 to 2013.
FIFA found the signing of 10 un-named players to be in breach of its rules covering the protection of minors. A fine of 450,000 Swiss francs ($509,000 US) was also imposed on Barcelona, which was given 90 days "to regularize the situation of all minor players concerned."
The Spanish Football Federation was also found by the world governing body to have violated the rules covering the registration of minors and fined 500,000 Swiss francs ($565,500).
Further details of the case were not provided, but Barcelona said in February that FIFA had sent a communication instructing it not to select six players who are under 18 for its youth matches — South Korea's Lee Seung Woo, Paik Seung-Ho and Jang Gyeolhee, Theo Chendri of France, Nigerian-Dutchman Bobby Adekanye and Patrice Sousia of Cameroon.
The punishment, which prevents Barcelona from signing any players until the summer of 2015, leaves recent agreements with Borussia Monchengladbach goalkeeper Marc-Andre Ter Stegen and Croatian teenager Alen Halilovic to join the club in July in limbo.
Barcelona, which has not commented on the sanctions, has three working days to inform FIFA of an intention to appeal and then a further week to provide its reasons for challenging the punishment.
Premier League club Chelsea had a one-year transfer embargo imposed after being found by FIFA to have induced teenager Gael Kakuta to leave Lens, but it was overturned in 2010 by the Court of Arbitration for Sport.
FIFA tightened its rules on transferring minors in 2010, to help end what global players' union FIFPro described as the equivalent of "child trafficking." FIFA sought to close loopholes which allowed clubs and agents to bring youngsters to Europe on the promise of getting a lucrative contract, only to abandon them without a job or education.
In the Barcelona case, FIFA stressed the "interest in protecting the appropriate and healthy development of a minor as a whole must prevail over purely sporting interests."
"The disciplinary committee emphasized that the protection of minors in the context of international transfers is an important social and legal issue that concerns all stakeholders in football," FIFA said in a statement. "Above all, the committee highlighted that while international transfers might, in specific cases, be favourable to a young player's sporting career, they are very likely to be contrary to the best interests of the player as a minor."
Barcelona potentially needs to sign a replacement goalkeeper, with Victor Valdes out of contract at the end of the season and ruled out for seven months this week following knee surgery. Gerard Pique is in need of an assured partner in central defence with the impending retirement of Carles Puyol.
The FIFA case threatens to further damage the image of a Catalan football institution that is owned by its members and prides itself as being "more than a club". It is currently grappling with the fallout from last year's signing of the 22-year-old Neymar.
Barcelona president Sandro Rosell abruptly quit in January as he fights a lawsuit alleging he misappropriated funds by hiding the real cost of Neymar's signing from Brazilian club Santos. In February, Barcelona paid 13.55 million euros (then $18.6 million) to Spanish tax authorities to cover any potential irregularities over the transfer, while maintaining its innocence of fraud charges.