Barcelona said on Sunday they will take legal action against Spanish newspaper El Mundo for publishing Lionel Messi's contract.
El Mundo published full details of the deal Messi penned with Barca in 2017 until June 2021.
Barca's last accounts showed their net debt had doubled to €488m, while the club's interim president Carles Tusquets said recently they had been forced to delay payments to players.
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Barcelona denied any responsibility for the publication of the contract in a statement, adding they regretted its release as it was a "private document governed by the principle of confidentiality between the parties".
The statement added:
FC Barcelona expresses its absolute support for Lionel Messi, especially in the face of any attempt to discredit his image, and to damage his relationship with the entity where he has worked to become the best player in the world and in football history.
Messi, who joined Barca in 2000 aged 13 and made his debut in 2004, is the club's all-time scorer with 650 goals and has also provided 280 assists in 755 appearances for the Catalans.
He is also their captain and most decorated player with 10 La Liga titles, four Champions Leagues plus six Copa del Rey triumphs.
The Argentine tried to leave Barca last August via a release clause in his contract but eventually decided to stay in order to avoid a court case with the club.
He can move to any club for free from June but has not ruled out staying at Barca, saying in a December interview that he will make his decision at the end of the season.
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