The FBI warned on Friday that Russian computer hackers had compromised hundreds of thousands of home and office routers and could collect user information or shut down network traffic.

The U.S. law enforcement agency urged the owners of many brands of routers to turn them off and on again and download updates from the manufacturer to protect themselves.

The warning followed a court order Wednesday that allowed the FBI to seize a website that the hackers planned to use to give instructions to the routers. Though that cut off malicious communications, it still left the routers infected, and Friday's warning was aimed at cleaning up those machines.