WASHINGTON — Laptops out, belts off, shoes in the bin — and don’t forget to pack carry-on liquids in a see-through plastic bag.

Passenger-screening rules became stricter and more time-consuming at U.S. airports after the Sept. 11, 2001 terrorist attacks, but that’s slowly changing, at least for some.

The Transportation Security Administration is relaxing its screening guidelines for frequent fliers and some international travelers willing to submit to pre-screenings.

On Friday, the agency announced it would expand that program, known as PreCheck, to the general public. The move would allow more passengers to walk through airport security without going through the usual cumbersome screening rituals.

The program “enables us to focus on the travelers we know the least about, adding efficiency and effectiveness to the screening process,” TSA Administrator John Pistole said in a statement Friday.

Pre-cleared travelers will have access to select screening lanes where they won’t be required to remove laptops, shoes, belts or light outerwear. Body and bag scans are still required.

Passengers can apply for the program through an online enrollment site beginning sometime this fall, according to the TSA. Applicants will have to provide personal information including name, gender, date of birth, Social Security number and addresses, in addition to paying a fee that the agency expects to set at $85.

Interested fliers must also submit identification and fingerprints in person at Washington Dulles International or Indianapolis International Airport, meaning participation is likely to remain limited for a while. The agency plans to add more enrollment sites nationwide in the future.

Twelve million passengers have already taken part in the pre-screening system, which operates at 40 U.S. airports, according to the TSA. But the program has raised concerns among privacy advocates, who say it gives the government another excuse to collect personal information.

“The logic of this program points us down a road of increasingly privacy-invading background checks by the government,” said Jay Stanley, a technology-policy analyst with the American Civil Liberties Union. “It confirms what we have feared for a long time, which is that the government will never have enough information.”

Another concern is that the program could allow the government to mine travelers’ online purchases and other Web-surfing habits. Applicants will sign waivers permitting screeners to “search various non-governmental/commercial data,” according to the TSA’s call for industry proposals in January.

Stanley also said he is concerned that the program would create a “traveling underclass” of rejected applicants, and that those who are wrongly denied would have no options for appeal and redress.

Democratic and Republican lawmakers who oversee the TSA have backed the agency’s plan.

“The expansion of TSA’s PreCheck program is a positive step towards greater risk-based screening and improving passenger’s travel experience,” said Rep. Michael McCaul, R-Tex., chairman of the House Homeland Security Committee.

Rep. Bennie Thompson (Md.), the panel’s ranking Democrat, said the program could give more non-threatening travelers “the type of less-invasive passenger-screening that frequent fliers and other handpicked populations have enjoyed for over a year.”

Both Thompson and McCaul cited the risk of potential abuses in their statements, suggesting that the expanded program will require transparency and oversight.

“As with all screening programs administered by TSA, the success of the endeavor will be dependent on effective communications with the public and effective management behind the scenes,” Thompson said.