Travellers to the U.S. could have their laptops and other electronic devices seized at the airport under new anti-terror measures.

They do not even need grounds to suspect wrongdoing.

The extent of the new powers, which have been secretly in place for some time, was revealed yesterday in the Washington Post.

They cover hard drives, flash drives, mobile phones, iPods, pagers, beepers, and video and audio tapes, as well as books, pamphlets and other written materials, the report said.

Copies of data must be destroyed when a review is completed and no probable cause exists to keep the information.

DHS officials insisted the policies were reasonable and necessary to prevent terrorism.