The agency responsible for security on America's transportation systems has confirmed that an external hard drive containing 100,000 staff records is missing.

The Transportation Security Administration (TSA), which is part of Homeland Security, has called in the FBI and the Secret Service to investigate whether the drive has been stolen or simply misplaced. 

The drive contains employee records from January 2002 to August 2005, including names, dates of birth, salaries, Social Security details and bank account numbers.

"At this point there is no evidence that any missing data has been improperly used," said an official TSA statement.

"However, the administrator is asking all employees to be extra vigilant and to carefully monitor bank statements, credit card statements, and any statements related to recent financial transactions."

The TSA said that it would provide affected employees with free credit monitoring services, and that anyone suffering identity theft would be given help to rebuild their identity.

It also promised to take action even if it turns out that the drive was lost instead of stolen.

"The TSA has zero tolerance for employees not following policies on data protection and will take swift disciplinary action, including dismissal, against individuals found to be in violation of our procedures," the TSA statement said.