Barcelona have released a statement declaring their outrage at Lionel Messi's "disproportionate" four-match ban from representing Argentina.
Messi was suspended for insulting the linesman during his national team's 1-0 World Cup qualifying win over Chile last week.
The ban was announced just hours before La Albiceleste's game away to Bolivia on Tuesday.
In the absence of their talisman, Edgardo Bauza's team lost 2-0 in La Paz, leaving them fifth in CONMEBOL qualifying and facing the prospect of needing to win an inter-confederation play-off if they are to reach next year's finals in Russia.
Messi's Barca team-mate Gerard Pique, speaking late on Tuesday, condemned the severity of the suspension and the club have now publicly issued a message of support for the 29-year-old forward.
"FC Barcelona expresses its surprise and indignation at the action by the FIFA Disciplinary Committee of suspending the player Leo Messi following the FIFA World Cup qualifying fixture between Argentina and Chile," a statement read.
"The club considers the four-match suspension finally imposed on the Argentine player to be unfair and totally disproportionate.
"Finally, FC Barcelona wishes to reiterate its support for Leo Messi, an exemplary player in terms of conduct both on and off the pitch."
The punishment relates to Messi's actions during the closing stages of Argentina's win at home to Chile, when the Barca star scored the only goal from the penalty spot.
The 29-year-old was penalised for a foul and proceeded to wave his arms and shout insults at the referee's assistant Marcelo Van Gasse, with whom he refused to shake hands at the final whistle.
Initially, the incident was not included in referee Sandro Ricci's report but was followed up by FIFA after video footage of Messi's insults emerged and they asked both the officials and the Argentinian Football Association (AFA) for their observations.
It means Argentina will also be without their talisman for next season's qualifiers against Uruguay, Venezuela and Peru, with him only returning for the final game of the CONMEBOL section against Ecuador.
Messi has also been fined 10,000 Swiss francs, while the AFA confirmed their intention to appeal the sanction.
Former Argentina and Barcelona coach Cesar Luis Menotti called the decision "nonsense", while Bauza lamented the timing of the ban following the loss to Bolivia.
"What surprised us was the little time we were given to release a legal response," he said.
"We had half an hour to send the first note. And after that, during the night hours, we stayed until four in the morning for the second note.
"It's strange because FIFA gives you the possibility to deliver an opinion to anyone who can be sanctioned. Not only he couldn't play, but we didn't have time to work with anyone else."