FIFA yesterday banned Spanish giant Barcelona from buying players for the next two transfer windows for "serious" breaches of rules on underage players.

FIFA's Disciplinary Committee found Barcelona and the Spanish Football Association (RFEF) guilty of making or allowing illegal deals.

As well as the transfer ban, which will effectively last 14 months, FIFA fined Barcelona 450,000 Swiss francs, (US$509,000). The Spanish champion was given 90 days to regularize the situation of all 10 minor players concerned.

A Barcelona source said the club was analyzing the situation and would make a statement at the appropriate time, but it is expected to appeal against the shock sanction.

Any appeal would have to be lodged with FIFA's Appeal Committee within three days and the club could take the case to the Court of Arbitration for Sport as a final measure.

The ban is a new blow to the image of Europe's most successful club of the 21st century following alleged tax evasion in its signing of star Brazilian Neymar.

If upheld, the ban would have serious consequences for Barcelona, especially with veterans Carles Puyol and injured goalkeeper Victor Valdes set to leave in June.

The Catalans were expected to complete the signing of German international goalkeeper Andre Ter-Stegen to replace Valdes.

The dramatic sanction follows an investigation last year by FIFA, whose rules state that a player has to be 18 to be transferred, unless the player falls into one of three specific cases. FIFA fined the RFEF 500,000 Swiss francs for its role in the underage player affair.

The dates of the Spanish transfer windows covered by yesterday's punishment are July 1-August 31 for the pre-season window and January 1-February 1 for the mid-season window.

The sanction came less than 24 hours after Barcelona's 1-1 home draw with Atletico Madrid in the Champions League quarterfinal first leg.

Barcelona's goal was scored by Neymar, whose scandal-mired transfer triggered the downfall of president Sandro Rosell and saw the club indicted for an alleged tax fraud of 13.5 million euros (US$18.59 million).

Meanwhile, Atletico striker Diego Costa is expected to miss the second leg, but has not torn his hamstring as first feared.

The Spanish international was replaced by Brazilian Diego Ribas, who scored the opener, after pulling up just 29 minutes into Tuesday' game.