A judge in the Barcelona suburb of Gava has accepted a tax-fraud complaint filed against Argentine soccer superstar Lionel Messi and his father and summoned them to appear in court for questioning, judicial sources said.

The judge accepted the complaint filed by the Spanish autonomous community of Catalonia's prosecutor's office for tax crimes, which accused the four-time world player of the year and FC Barcelona standout and his father of defrauding the Spanish state of some 4.1 million euros ($5.5 million).

The allegations refer to taxes on income from endorsements that the player allegedly failed to report on his 2007, 2008 and 2009 tax returns.

Messi has been summoned to appear in court on Sept. 17 as part of a legal process that could lead to charges being brought against the soccer star, who has lived in Spain since he was a teenager.

Prosecutors contend that Messi's father, Jorge Horacio Messi, began laying the groundwork for the ostensible evasion scheme in 2005, when Lionel was still a minor.

Jorge Messi arranged to transfer revenues from countries where large sums were paid for use of the player's image to shell corporations domiciled in tax havens, they say.

Lionel Messi has retained one of Barcelona's top criminal defense attorneys, Cristobal Martell, to represent him, court sources told Efe.

Messi and his father have the option of negotiating with Spain's tax agency to regularize their situation. If the case goes to trial, however, any such accord would require the approval of prosecutors.

The Barça forward could also avoid a trial if his father were to accept sole responsibility for the alleged tax evasion, the court sources said.

Lionel Messi denied the accusations in a statement released on June 12, the day the complaint was filed.

"We have always fulfilled all of our tax obligations, following the advice of our tax consultants, who will take care of clarifying this situation," the player said on his Facebook page.

Messi and his father are accused of three counts of tax evasion, each of which is punishable in Spain by up to six years in prison.