Italian officials, while pointing out that hauls of counterfeit money and Treasury bills were not unusual, were stunned by the amount involved. Investigators are looking into the origin and destination of the fakes.

Italian prosecutors revealed last month that they had cracked a $1 billion bond scam run by the Sicilian Mafia, with the alleged aid of corrupt officials in Venezuela's central bank. Twenty people were arrested in four countries.

The fake bonds were to have been used as collateral to open credit lines with banks, the Reuters news agency reported. The Venezuelan central bank denied the accusations.