The FBI and the Department of Homeland Security (DHS) are investigating what could be the first known foreign cyber attack to damage an American industrial system.
Federal investigators confirmed to Sky News that they were examining reports that a foreign hacker or hackers managed to remotely gain access to a water facility in Illinois and shut down a pump on November 8.
The incident came to light after prominent cyber security expert Joe Weiss obtained a report written by the Illinois Statewide Terrorism and Intelligence Centre.
According to Mr Weiss, who specialises in protecting industrial control systems from electronic threats, the report confirms the cyber attack was traced back to a computer in Russia.