Cabinet secretaries, top congressional leaders and an exclusive group of senior U.S. officials are exempt from toughened new airport screening procedures when they fly commercially with government-approved federal security details.

Aviation security officials would not name those who can skip the controversial screening, but other officials said those VIPs range from top officials like Treasury Secretary Timothy Geithner and FBI Director Robert Mueller to congressional leaders like incoming House Speaker John Boehner, who avoided security before a recent flight from Washington's Reagan National Airport.

The heightened new security procedures by the Transportation Security Administration, which involve either a scan by a full-body detector or an intimate personal pat-down, have spurred passenger outrage in the lead-up to the Thanksgiving holiday airport crush.

But while passengers have no choice but to submit to either the detector or what some complain is an intrusive pat-down, senior government officials can opt out if they fly accompanied by government security guards approved by the TSA.

"Government officials traveling with approved federal law enforcement security details are not required to undergo security screening," TSA spokesman Nicholas Kimball said, speaking about checkpoint security at airports. "TSA follows a specialized screening protocol for federal law enforcement officers and those under their control, which includes identity verification."

The TSA would not explain why it makes these exceptions. But many of the exempted government officials have gone through several levels of security clearances, including FBI background checks, and travel with armed law enforcement, eliminating the need for an additional layer of security at airports.

Armed law enforcement officials who travel commercially are also allowed to skip airport security after they fill out the proper paperwork at the airport.

Some members of President Barack Obama's Cabinet, including Defense Secretary Robert Gates, Secretary of State Hillary Rodham Clinton, Attorney General Eric Holder and Homeland Security Secretary Janet Napolitano, travel almost exclusively on government or military planes and are therefore not subject to airport security.

Geithner travels with a Secret Service detail, for example, the only Treasury official with such a security exception. When Mueller and John Morton, head of Immigration and Customs Enforcement, travel on commercial airlines with their federal security details, they also skip the lines, machines and pat-downs.

Same goes for Boehner, the top House Republican, who was sighted last week being guided past security lines at Reagan. Spokesmen for both Boehner and current House Speaker Nancy Pelosi would not discuss security arrangements. But under a policy started by the Bush administration after the Sept. 11 attacks, a military aircraft is made available to the speaker, third in line to the presidency, for all official flight needs.

Senate Sergeant at Arms Terrance Gainer said the only Congress members with protective details are leaders, "based upon a threat analysis conducted by the (U.S. Capitol Police) and affirmed by the Capitol Police Board." Gainer added that members "with sworn protection" are able to avoid security because "their secure posture is affirmed by the law enforcement process established by TSA."

Senate Majority Leader Harry Reid flies commercial, has a security detail and does not go through security, spokesman Jim Manley said. The assistant Senate Democratic leader, Richard Durbin of Illinois, flies commercial and has a security detail — mainly when he's in Washington. His office said he goes through the security line like other passengers.

Rep. James Clyburn of South Carolina, the House Democratic whip, flies commercial, has a security detail and goes through regular airport security, spokeswoman Kristie Greco said.

Senate Republican leader Mitch McConnell flies commercial, spokesman Donald Stewart said, who also would not detail his security arrangements.

A spokesman for incoming House Majority Leader Eric Cantor declined to discuss his arrangements. Daniel Reilly, a spokesman for outgoing House Majority Leader Steny Hoyer of Maryland, said he flies commercial, but also would not discuss security.

A few lawmakers have called for investigations into the intimate pat-downs, and some refuse to go through the full-body imaging machines when they travel. Rep. Jason Chaffetz, R-Utah, who has blasted the procedures, avoids the scanners but goes through security and takes the pat-down if it's required, according to his spokeswoman Alisia Essig.

The TSA's administrator, John Pistole, is treated like any other traveler when he flies, waiting in security lines and walking through X-ray machines, including the full-body imagers, his spokesman said.

Even as he has led a publicity campaign in recent days to urge cooperation from air travelers, Pistole's agency is preparing for long lines at airports Wednesday, the busiest travel day of the year.

Security checks at some U.S. airports could be slowed this year by a loosely organized campaign for travelers to opt out of going through the full-body imaging machine, a 10-second process. By opting out, travelers would be choosing to undergo a pat-down which can take up to four minutes.

This year's pat-downs are different from last year. The new version includes a rigorous screening that includes agents running their hands inside a passenger's legs and along the cheek of the buttocks as well as direct contact with the groin area.

The terrorist threat to commercial aviation, including a failed attack on a Detroit-bound jet last Christmas, prompted the Obama administration to develop a more invasive pat-down on air travelers.

About two-thirds of Americans support using the full-body scanners to increase security, according to a Washington Post-ABC News poll published Tuesday. But half of the 514 adults surveyed by phone said the more rigorous pat-downs go too far.

The American Civil Liberties Union has received more than 600 complaints over three weeks from passengers who say they were subjected to humiliating pat-downs at U.S. airports, and the pace is accelerating, according to ACLU legislative counsel Christopher Calabrese.

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Associated Press writers Laurie Kellman, Martin Crutsinger and Larry Margasak contributed to this report.