Later Tuesday, Nicholson acknowledged that the data theft involved identities of about 2.2 million soldiers, sailors, airmen, and marines, including up to 1.1 million members on active duty, 430,000 members of the National Guard, and 645,000 members of the Reserves.
Last weekend, VA said that some active-duty members' data was among the 26.5 million stolen identities, but revised the estimate Tuesday after comparing both VA and Department of Defense data.
"The Department will continue to make every effort to inform and help protect those potentially affected, and is working with the Department of Defense to notify all affected personnel," said Nicholson in a statement Tuesday.
The data loss was characterized by a Pentagon spokesman was "the largest [ever] I am aware of."
In associated news, the Montgomery County, Maryland police department, which is managing the $50,000 reward posted by the FBI and VA for the return of the laptop and external drive, on Tuesday described the stolen hardware.
The laptop, an Hewlett-Packard (HP) Pavilion ZV5360 and the drive, an HP External Personal Media Drive, may have been sold because "the suspect or suspects responsible for the theft did not have knowledge of what information was stored on the hard drive," the department said in a statement. "Anyone who may have this stolen property can turn it in anonymously and become eligible for the reward," the statement continued.