MADRID - The Argentinian football player Lionel Messi along with his father, who is also his manager, must appear in court next September on possible charges of tax fraud, local media reported on Thursday.

Messi and his father, Jorge Horacio Messi, are charged with defrauding the Spanish treasury more than 4 million euros ($6.6 million) in tax declarations of 2007, 2008 and 2009.

They sold Messi's image rights to foreign countries avoiding paying taxes in Spain, where Messi plays with FC Barcelona.

The four-time world player of the year and FC Barcelona denied last week these accusations.

"We have found out through the press of the actions begun by the Spanish prosecutor. This is something that causes us surprise because we have never committed any infraction," Messi published on Facebook.

If found guilty, Messi and his father could face a fine of six times the amount of money supposedly defrauded and a penalty of between one and five years in prison, although his father could face more responsibility as accusation said "the initiative to commit fraud came from Jorge Messi."

Barcelona' Lionel Messi looks on during their Spanish First Division soccer match against Real Betis at Benito Villamarin Stadium in Seville in this Dec 9, 2012 file photo. [Photo/Agencies]

Jorge Messi, father of Argentina's Lionel Messi, watches his son play against Colombia in the first round of the Copa America soccer tournament in Santa Fe, in this July 6, 2011 file photo.  [Photo/Agencies]