An audit at the US State Department has revealed the loss of over 1,000 laptops, some of which held security information.

Around $30m worth of computing hardware is "unaccounted for", the bulk of it laptops. These include over 400 from the Anti-Terrorism Assistance Program, some containing security material.

Nita M. Lowey, a representative on the House Appropriations subcommittee that oversees State Department operations, told Congressional Quarterly that she is "concerned" about the security revelations.

"The importance of safeguarding official laptops and office equipment containing sensitive information is not a new concern," she said through a spokesman. "I intend to review the facts about this situation."

Officials have apparently known of the problem for some time. John Streufert, an official in charge of computer equipment at the State Department headquarters in Foggy Bottom, warned in February of a "significant deficiency" in laptops.

Officials discussed the problem and agreed to act before the issue "blows up ".

The situation has been compared to the loss of a laptop by the Veterans Administration in 2006 which held personal details on 23 million veterans.