Some security measures introduced at US domestic airports after the 11 September attacks are being relaxed, government officials have announced.

Car parks close to airport terminals are being allowed to re-open and fewer passengers will be screened at the departure gate.

Parking was barred within 300 feet (91 metres) of an airport terminal building to prevent car bombings in the wake of 11 September.

Random gate screening is an imperative part of a continuous deterrent exercise

Admiral Loy Transportation Security Administration

However the rule will be re-imposed if the level of alert rises.

The new arrangements mean that second searches of passengers will be carried out on a selective basis at the main screening point rather than the gate.

"We are going to reduce the hassle-factor by reducing the amount of gate screening we're doing," US deputy transportation secretary Michael Jackson as saying.

However some random searches will still be carried out at the gates.

"We believe random gate screening is an imperative part of a continuous deterrent exercise", said Admiral James M. Loy, under secretary of transportation for security.

Other improvements - including better screening at the main checkpoint, better cockpit doors, the presence of sky marshals on flights - made it possible to reduce screening at the gates, he said.

Passenger concerns

Under the new arrangements, before arriving at the security checkpoint nearly all passengers will have to obtain a boarding pass which will indicate to staff whether they have been selected for further scrutiny.

Transport Security Administration spokesman Brian Doyle said the changes in procedures aimed to enhance the security system.

According to airport representatives, air travel has become safer since 11 September, with more efficient baggage screening, better-trained staff and background checks on airport employees.

However airports have complained of revenue loss due the closure of car parks which is thought to have partly prompted the decision.

Passengers interviewed by News 12 radio station at MacArthur airport on Long Island were concerned the lifting of restrictions could jeopardise safety.

"If you have to sacrifice comfort for security then that that's the way you have to go," said Jean-Pierre Turgot.

"Whatever is going to make us safer I think we should do," said another passenger.