The United States has told 58 foreign airlines their passengers will be subject to extremely thorough and long searches on arrival unless the airlines provide information needed to spot possible terrorists, US media reported.

Under a new aviation security law signed by President George Bush, passengers on Saudi, Russian, Chinese and other foreign airlines will be subjected to the new measures.

Media reports said the commissioner of customs, Robert Bonner, had told airlines that if they failed to comply customs inspectors would search "all hand-carried and checked baggage on every flight arriving in the United States".

Any delay in implementing the measure could put security at risk, he said.

The searches could add hours to the clearance process for overseas travellers.

The letter was sent to 58 carriers, including Saudi Arabian Airlines, Royal Jordanian Airlines, Pakistan International Airlines, Ethiopian Airlines, Aeroflot and Air China.

Under the law, airlines had two months to begin the electronic transmission of passenger lists for all flights to the United States.

The Customs Service said it had received very few responses.

A spokesman for the Jordanian airline said it would comply, while other carriers said they did not know much about the new requirement or were still studying it, it added.

For more than a decade, federal officials have been asking airlines to participate in the system used to compare biographical data on international air travellers with lists of suspected terrorists and criminals.

Lists are compiled by law enforcement and intelligence agencies.

The Customs Service checks the names against several databases, including the Interagency Border Inspection System and files maintained by the Federal Bureau of Investigation.