China and Russia are accused in a US Congressional report of being the worst perpetrators of economic cyber espionage.
An intelligence report issued on Thursday said they are using cyber espionage to steal US trade and technology secrets to bolster their own economic development.
The report said this poses a threat to US prosperity and security.
The report to Congress was titled "Foreign Spies Stealing US Economic Secrets in Cyberspace." It was compiled by the office of the National Counterintelligence Executive and covers the period 2009 - 2011.
The report said intelligence services, private companies, academic institutions and citizens of dozens of countries target the United States. But it only named China and Russia.