Naples prosecutors said Tuesday they had ordered the search of dozens of Italian club offices as part of a tax evasion investigation relating to player contracts.
Financial police were executing search warrants to seize documents from most of the 20 clubs in Serie A, including AC Milan, Juventus and Lazio, in addition to clubs in lower divisions.
A statement by Naples prosecutors indicated some foreign clubs also were part of the investigation, but they did not identify them.
Prosecutors said the clubs were under investigation for alleged conspiracy to avoid payment of "huge amounts of money'' to tax authorities during the transfer of players. The clubs were also accused of "systematic'' billing for nonexistent transactions.
The seized material detailed the relationship between clubs, players and sports agents, their contracts as well as television rights.
Inter President Massimo Moratti said his club had handed over documents concerning past transactions.
"It wasn't a search, just a request for past documentation,'' Moratti said in comments to reporters that were posted on the Inter website.
"Nothing to be concerned about.''
Italy has been on a wholesale crackdown on tax cheats in a bid to recover the estimated 20 per cent of Italy's GDP that is lost to tax evasion each year. Several high-profile athletes have been caught up in the crackdown, including seven-time motorcycling world champion Valentino Rossi and more famously Diego Maradona.
The statement from prosecutors made no mention of any players, team officials or sporting agents being placed under investigation.
Fenerbahce have been banned from European club competition for two seasons and fellow-Turkish side Besiktas for one, European football’s governing body UEFA said on Tuesday.
The ruling means Fenerbahce will be barred from next season's Champions League and Besiktas will miss out on the Europa League. Both bans were connected with match-fixing in domestic games in 2011.