Barcelona striker Lionel Messi will head to China early on Thursday to join the Argentina squad for the Olympics, which get underway next week, the Spanish club said.

The 21-year-old will fly from Italy, where he took part in a 3-1 friendly win over Fiorentina in Florence on Wednesday night, in the company of Pepe Costa, a member of Barcelona's technical staff, the club said in a statement.

The Argentina international has been at the center of a tug of war between club and country with Barcelona trying to retain him for its Champions League qualifier tie in August.

Earlier on Wednesday, FIFA confirmed clubs are obliged to release players aged 23 and under for the Olympics, but Barcelona said it would take the case to the Court of Arbitration for Sport (CAS).

A FIFA judge declared that clubs were under an obligation to release their under-23 players for Beijing. Messi said: "If FIFA say I should be there then I'll go without waiting for the CAS ruling."

Messi added: "If CAS say that I have to return then I'll come back but for the moment I want to be with my country and my teammates."

The player will miss Barcelona's pre-season tour of the United States. The team will face Mexican side Chivas de Guadalajara in Chicago on Sunday and the New York Red Bulls three days later in New York.

The Olympic soccer tournament, which takes place from Aug 6 to 23, clash with the dates of the Champions League preliminary round, set to be played on either Aug 12 or 13.

A statement issued by world football's governing body FIFA confirmed FIFA's previous ruling that it was "mandatory" for players to be released for Olympic duty.

A FIFA judge was called to rule on the matter after Werder Bremen, Schalke and Barcelona questioned FIFA's stance as the Olympics do not appear on FIFA's official calendar.

Bremen and Schalke are unhappy with the inclusions of Diego and Rafinha, respectively, in the Brazil squad.

CAS had been expected to have the final say in the matter but earlier on Wednesday claimed it did not have the jurisdiction to arbitrate between Olympic committees and professional football clubs.