But on its own, the watch list cannot be used to prevent passengers from boarding flights, nor can it impel extra screening at security checkpoints, according to the document. That has raised questions about whether it serves a legitimate security purpose, and has heightened civil liberty concerns over the added government surveillance.
“If I’m running late, having a bad day and I’m rude to the screeners, do I get put on the list?” said Fred Burton, the chief security officer at Stratfor, a global intelligence company in Austin, Tex.
“The bottom line is that in the post 9/11 world, do we really need another watch list — particularly one from the T.S.A., which is not an intelligence agency?” said Mr. Burton, a former deputy chief of counterterrorism at the State Department’s Diplomatic Security Service.
On Thursday, lawmakers demanded more details about the watch list, which had not been previously disclosed, and suggested that the agency notify people who have been added to it.
“T.S.A. has an important job to do, and I want T.S.A. officers to be safe and secure,” Representative Bonnie Watson Coleman, Democrat of New Jersey, said during a House homeland security subcommittee hearing. “What I don’t want — what I think no American would want — is an excuse for unfair, secret profiling that doesn’t even offer a chance for people to contest their name appearing on such a list.”
So far, the names of fewer than 50 people have been put on the watch list, said Kelly Wheaton, a T.S.A. deputy chief counsel.
But two other government security officials who are familiar with the new watch list, describing it on the condition of anonymity because they were not authorized to discuss it, said that the number of names on the list could be higher, with travelers added daily.
The guidelines prohibit profiling based on race, religion or gender, and said those categories could not be used as the sole reason for including a passenger on the watch list. But the directive obtained by The Times said such factors could be used when they are relevant and fit specific intelligence.
Mr. Wheaton said the new list aims to protect airport security screeners from travelers who previously have been demonstrably unruly at, or near, checkpoints. He said screeners were assaulted 34 times last year, up from 26 in 2016.
Matthew F. Leas, a T.S.A. spokesman, said in an email that the agency “wants to ensure there are safeguards in place to protect Transportation Security Officers (TSOs) and others from any individual who has previously exhibited disruptive or assaultive behavior at a screening checkpoint and is scheduled to fly.”
The United States government already maintains a bevy of watch lists.
The most well known, maintained by the F.B.I., is a large database of the names of more than one million people — including tens of thousands of American citizens or legal residents — who are known or suspected terrorists. Officials rely on that database to compile the no-fly list that has been criticized for barring travelers based on mistaken identities, including prominent politicians, celebrities and young children.
The Secret Service maintains a watch list of people who pose a potential threat to government officials or buildings. It publicly discloses the types of information it collects in the database, but not the names that are on it.
But the new T.S.A. database, according to people familiar with it, includes travelers who have simply had a verbal altercation with security officers or have taken other actions that the agency said interferes in the screening process.
Civil liberties groups said that makes it even more likely that individuals who do not pose a threat to airports or planes will be swept up in the United States’ homeland security system.
“While people on the list are not necessarily subject to additional scrutiny, it seems likely that agents would single them out for additional attention, and there is no way to get off the list,” said Faiza Patel, a director of the Liberty and National Security Program at New York University’s Brennan Center for Justice.
She said that because the watch list will be shared with other law enforcement agencies, “it will be difficult to control the consequences.”
Federal security directors, top T.S.A. security officials at airports and top Air Marshals supervisors can nominate individuals to be put on the watch list. Only the T.S.A. administrator, his deputy and the top two officials at the agency’s Office of Intelligence and Analysis may add or remove people from the database.
The directive obtained by The Times does not specify how members of the public can appeal being included on the list.
Government watchdogs have long criticized such watch lists, especially after evidence concluding that as high as 35 percent of the names that are designated for inclusion are either outdated or added without adequate factual basis. Individuals are denied any meaningful way to correct errors and clear their names.
In recent years, the government has established rules that are intended to prevent intelligence agencies from keeping secretive, open-ended watch lists based on suspicions that are ultimately unfounded.
The T.S.A. security operations have long been criticized for targeting racial and religious minorities for extra screening. A number of African-American women have said screeners have searched their hair, even after the agency said the practice was halted.
Most recently, the agency apologized to Navdeep Bains, Canada’s minister of innovation, science and economic development, after he was repeatedly asked by screeners at the Detroit Metropolitan Airport to remove his turban. Mr. Bains, who was in the United States to deliver a speech, is a Sikh whose religion requires him to wear a turban.
The agency later admitted that surveillance video showed that the screener did not follow standard operating procedures, and said that the screener had received additional training as a result of the episode.
