As dozens of images taken by full-body scanners at airports leaked on internet, the US has sought to quell complaints about the new equipment and pat-down search saying not all travellers are subject to the enhanced checking.
The government says most of the passengers won't be subjected to full-body scans or pat-downs at airports and the hype swirling around a few higly publicised cases does not reflect the reality of the new safety inspections, according to the Los Angeles Times.
In the first two weeks after the enhanced screening measures began Nov 1, the Department of Homeland Security said about 700 of an estimated 28 million airline passengers lodged complaints with the Transportation Security Administration (TSA).
The TSA said that the pat-downs are rare - involving 3 percent of all airline passengers - and that travelers can request that they be done in a private room.
Of the passengers asked to submit to a full-body scan, 1 percent have chosen to instead undergo a pat-down, which includes TSA agents using their hands to check sensitive areas such as the groin and bra area, the report said.
The government has been facing criticism after videos showing x-ray images of passengers circulated worldwide through internet.
In one video, TSA agents at the Salt Lake City airport were performing a pat-down on a young boy after his father decided to remove the boy's shirt. In another widely-seen YouTube clip, San Diego native John Tyner warns agents not to "touch my junk" as he refuses to submit to either a full-body scan or a pat-down.
Federal officials have said that under the new policy, most passengers will continue to pass only through metal detectors. A smaller group will be asked to submit to a body scan. Only passengers who refuse the body scan or trip the alarm on the metal detector will be asked to undergo a pat-down.
TSA agents can allow passengers who trip the metal detector to check again for any metal and pass through the detector again.
With the body scanners, the TSA uses software and other technology that blurs the faces of passengers or doesn't pick up facial features.
In terms of radiation exposure, the energy is thousands of times less than that of a cellphone transmission, federal officials said.
The scanners do not store the images.
White House Press Secretary Robert Gibbs said the government was constantly reevaluating security techniques, saying they "have to evolve."
"Our goal must be to maximise protection and security and minimise inconvenience and invasiveness," Gibbs was quoted as saying. "It's not an easy task."