Customs agents have the prerogative to examine and even copy data from travelling citizens' laptops they search, CNN's American Morning reports.

"A new alert for travellers: be careful what you store on your laptop or your BlackBerry when entering the United States," warns CNN's John Roberts. "Customs agents can examine your computer and even keep your private information."

CNN reporter Jeanne Meserve adds ominously, "Your banking records, your music choices, your emails, your business contacts -- all can be examined, copied and stored by the government when you enter the country, if they're in an electronic device."

One Pakistani-American IT consultant says that U.S. agents searched his computer on five occasions upon returning from overseas trips, even forcing him to give them access to confidential corporate information.