Investigating whether counterfeit routers and computer hardware from China were installed in U.S. government computer networks, the FBI has recovered about 3,500 fake devices that were worth about $3.5 million, Reuters reports.

The investigation, code-named Operation Cisco Raider, started due to concerns that counterfeit network components could allow hackers to access secure U.S. databases.  Among the recovered bogus components were pirated versions of Cisco Systems routers, switches, interface converters and wide area network interface cards.

According to Reuters, one U.S. official, who spoke on condition of anonymity, said the components FBI discovered had not harmed government computer systems, failing to make them vulnerable.

A Cisco spokesman said that the company had not found any dangerous counterfeit product, saying the counterfeiters were not interested in accessing U.S. top secret information, but in copying high volume products to make a quick profit.

“We did not find any evidence of re-engineering in the manner that was described in the F.B.I. presentation,” said John Noh, a Cisco spokesman, as quoted by the New York Times. “We know what these counterfeiters are about.”

Catherine L. Milhoan, an F.B.I. spokeswoman, said the agency did not try to suggest the Chinese government was involved in the counterfeiting issue.

 “We worked very closely with the Chinese government,” she said, adding that arrests had been made in China following the investigation. “The existence of this document shows that the cyber division of the F.B.I. has growing concerns about the production and distribution of counterfeit network hardware.”

Despite the reassuring declarations from Cisco, several industry executives and technologists said they believed more importance should be given to counterfeit products, which represent a real danger to government computer networks.