Many women had complained that a new “patdown method”, introduced in September after two Chechen women were blamed for blowing up flights in Russia, killing 90 people, was too intrusive.

Airport screeners will revert to checking around the “chest perimeter” unless the passenger sets off an explosives alarm. This can include checks under the bra but not hand searches between the breasts. “We’ve made it more of a perimeter patdown, but we’re still getting the security value,” Mark Hatfield, director of communications at the Transportation Security Administration, said .

Between 400 and 500 women had lodged formal complaints that they were touched inappropriately after being randomly selected or setting off metal detectors, he said.

The rules had given screeners more latitude to check passengers manually based on “visual observations”.

After women objected, the Government clarified that screeners had been instructed to “use the back of the hand when screening sensitive body areas, which include the breasts (females only), genitals and buttocks”.

Mr Hatfield said that he had been inundated with calls about the impact on female passengers of the new policy and suggested that people were overreacting. “This is a gender-neutral story,” he said. “It applies to men and women.”

The patdowns are performed by screeners of the same sex as the passenger.

Despite changing the rules, the Government defended its screeners yesterday. Six million patdowns had taken place since September, suggesting that screeners were doing a good job of making women feel comfortable given that only a few hundred had lodged complaints, Mr Hatfield said.

Manual checks were essential until new technologies were developed, he said. “The bad guys are thinking of new ways to hurt us every day and we have to be one step ahead.”

A document scanner that picks up explosive traces and an air jet system that finds minute residues of explosives on a passenger are already being tested. A passenger X-ray system to discover hidden objects will be field tested early next year.

Fears that suicide bombers may try to board US aircraft came to the fore in August, when two Russian airliners were brought down en route from Moscow to cities in southern Russia.

The female suspects, dubbed “black widows” by the Russian media because they were thought to be avenging deaths of male Chechen relatives at the hands of Kremlin forces, reportedly bribed their way on board having been briefly detained by police.

Explore World News

• Iraq News

• US & Americas News

• Europe News

• Middle East News

• Asia News

• Africa News

• Ireland News

Times Recommends

• 'Great Schlep' may seal the deal for Barack Obama
• Hindu 'storm troopers' flex their muscles
• Ahtisaari: deserved reward for (failed) plan