The Portuguese revenue authority is investigating alleged tax fraud by clubs and football players, including Portuguese and Real Madrid star Cristiano Ronaldo.
Ronaldo has been accused by the Spanish authorities of defrauding the authorities of around $16.8 million between 2011 and 2014, but on Tuesday denied the allegations, reports Xinhua news agency.
Madrid's state prosecutor has alleged that Ronaldo used a shell company in the Virgin islands to hide his total income from Spain's tax office.
GestiFute, a firm representing several footballers defended on Tuesday that Ronaldo is compliant with his tax payments. Ronaldo has also told journalists he has nothing to hide.
Real Madrid said in a statement it had "full trust" in its player, who they believe has "complied with his fiscal obligations".
The operation is taking place at a European scale, with several tax authorities looking for traces of fiscal fraud in football.
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Ronaldo was the highest earning athlete in the world last year, according to Forbes, making around $86.1 million.
--IANS
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