Veterans affairs officials said there was no evidence the information had been used but acknowledged it had exposed military veterans to the risk of identity theft.

"This data contained identifying information including names, social security numbers, and dates of birth for up to 26.5 million veterans and some spouses, as well as some disability ratings," VA secretary Jim Nicholson said in a letter to veterans.

"The employee's home was burglarized and this data was stolen," he said.

The department said the employee was not authorized to take home the data and has been placed on administrative leave pending an investigation.

"Appropriate law enforcement agencies, including the FBI and the VA (Veterans Affairs) Inspector General's office, have launched full-scale investigations into this matter," it said.

The department, which handles health and other benefits enjoyed by veterans of US military service, said the data did not include either health records or financial information.

It was believed unlikely that the information was the target of the burglary, which occurred earlier this month, the department said.

Officials said there had been other similar, burglaries in the same neighborhood.

"It is possible that (the burglars) remain unaware of the information which they possess or of how to make use of it," it said.

It urged veterans to check for bank statements, credit card statements or other financial statements for any unusual activity.

"I've got to ask, and I've got to ask it not only of the VA but all of government, why can a data analysts take all that information home?" said Senator Larry Craig, chairman of the Senate Veterans Affairs Committee.

"That is a breach of security in today's concern about ID theft that is huge, and I think it wakened the secretary to the vulnerability within his own organization, and that is true I would guess across government," he said in an interview with CNN.

The VA said it was notifying all affected veterans of the loss by letter, and directed veterans to two websites (www.firstgov.gov and www.va.gov/opa) and a toll free telephone number for more information.

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