Defense department officials would not publicly confirm the ban, although messages were sent to department employees informing them of the new restrictions. As part of the ban, the Pentagon was collecting any of the small flash drives that were purchased or provided by the department to workers, according to one message distributed to employees.

Workers are being told there is no guarantee they will ever get the devices back and it is not clear how long the ban will last.

The issue of flash drives has also been of concern at the Department of Homeland Security. An audit by the Department of Homeland Security Inspector General recommended that the agency implement greater procedures to ensure that only authorized computer flash drives or other storage devices can be connected to the network there and that an inventory of those devices be set up.

The Department of Homeland Securityagreed with the recommendations and said some of that is already being done. They also said that more software enhancements are in the works that will provide more protection.