Authorities in Italy have frowned at the issuance of 'false visas' to footballers who entered the country from Africa.

Italian police are investigating football clubs for allegedly getting young African players false papers in a probe that could involve Serie A teams.

The inquiry centres on AC Prato, which plays in the Lega Pro league, amid suspicions managers "favoured the illegal entry into Italy of African minors, some of whom were then sold to superior clubs," the Gazzetta dello Sport said.

The daily said the offices of two unnamed Serie A teams and one Serie B team were searched as part of the probe, but added that the teams were believed to have bought the players without knowing about the fraud.

Managers in Prato are also suspected of match-fixing, the reports said. Four people including two of the managers were detained by police on Thursday.

The Lega Pro is the third professional division, below Serie A and B.