At issue is what is called the government's "no-fly" list, a list of names compiled by the Transportation Security Administration, the agency responsible for protecting airline travel. The list contains names of people who are barred from flying because they are considered a threat or have links with suspected terrorists.

But now a group of people who say they have been wrongly put on the list are challenging the no-fly list in federal court.

The suit is being filed by the American Civil Liberties Union on behalf of seven people who say they are innocent of any links to terrorists and pose no risk to fellow travelers. Among those filing suit are a retired minister, a college student, a member of the U.S. military and a lawyer for the American Civil Liberties Union, David Fathi.

Mr. Fathi told a Washington news conference that he has been stopped, interrogated（审讯）and in some cases briefly detained because security officials at airports have told him his name appears on the government's no-fly list.

"I have been led away by armed police. I have been threatened with indefinite detention and I have had one officer tell another to put me in handcuffs and take me away. Now I have a pretty thick skin. But when these things happen not just once, but over and over again, it is humiliating（羞辱性的）and it is frightening. I am not a terrorist and the government has no reason to put my name on a list of suspected terrorists."

The seven travelers filing suit are represented by ACLU lawyer Reginald Shuford. He says several were stopped at airports even though they had a letter from the Transportation Security Administration acknowledging that they do not pose a security threat.

"They are questioned about everything from who they are, their national backgrounds, where they are going, whether or not they have any affiliation（联系）with certain 'terroristic activity.' And the worst part of all, beyond the stigma, is that there is no way at all to clear one's name from the no-fly list once you are placed on it."

There was no immediate response to the lawsuit from the government. But in the past, Transportation Security Administration officials have said the no-fly list is an essential tool in the war on terrorism. TSA spokesman Mark Hatfield told the Associated Press that the agency is aware that problems exist with the no-fly list, but said government officials have worked with those wrongly placed on the list to clear their names.

The ACLU lawsuit was filed in a federal court in Seattle, Washington. The suit calls for the government to maintain the no-fly list in a way that does not stigmatize（污蔑）or inconvenience innocent travelers.