FBI officer told "Reuters" that a hacker group linked to " Anonymous " hacked during the last week U.S government computers in multiple agencies and stole sensitive information in a campaign began nearly a year ago .
A memo distributed on Thursday described these attacks as a " widespread problem that must be addressed " . According to this memo the list of hacked sites included U.S. military , energy and Health and Human Services and perhaps many other agencies . Investigators are still collecting information about the size of this electronic campaign that authorities believe it will continues.
The FBI memo advise systems managersto be cautious beacuse their systems will be at a high risk.
A spokeswoman of Investigation's Bureau refused to give any other details .