WASHINGTON (Reuters) - A U.S. watch list of terrorism suspects has passed 1 million records, corresponding to about 400,000 people, and a leading civil rights group said on Monday the number was far too high to be effective.

The "Tribute in Lights" shines on the skyline of lower Manhattan as the sixth anniversary of the attack on the World Trade Center is observed in New York, September 11, 2007. REUTERS/Gary Hershorn

The Bush administration disagreed and called the list one of the most effective tools implemented after the September 11 hijacked plane attacks -- when a federal “no-fly” list contained just 16 people considered threats to aviation.

The American Civil Liberties Union publicized the 1 million milestone with a news conference and release.

It said the watch list was an impediment to millions of travellers and called for changes, including tightening criteria for adding names, giving travellers a right to challenge their inclusion and improving procedures for taking wrongly included names off the list.

“America’s new million-record watch list is a perfect symbol for what’s wrong with this administration’s approach to security: it’s unfair, out-of-control, a waste of resources (and) treats the rights of the innocent as an afterthought,” ACLU technology director Barry Steinhardt said in a release.

President George W. Bush ordered in the current list in September 2003 as a way to wrap several growing terrorism watchlists into a single government database compiled and overseen by the FBI, through a Terrorist Screening Center.

Suspected terrorists or people believed to have links to terrorism are included on the list, which can be used by a wide range of government agencies in security screening. About 50,000 individuals are included on the Transportation Security Administration “no-fly” or “selectee” lists that subject them to travel bans, arrest or additional screening.

Critics have pointed to troubles that figures such as U.S. Sen. Edward Kennedy, 1960s civil rights leader Rep. John Lewis and singer Yusuf Islam (formerly Cat Stevens) have had with watch lists as evidence the consolidated database is poorly managed.

The Terrorism Screening Center, which maintains the list, has already put in place several steps to ensure the list is accurate and up-to-date, spokesman Chad Kolton said.

He cited a report last year by the Government Accountability Office that said there was general agreement within the federal government that the watch list had helped to combat terrorism.

“The list is very effective. In fact it’s one of the most effective counterterrorism tools that our country has,” he said.

About 400,000 individuals are included on the list, about 95 percent of whom are not U.S. citizens or residents, Kolton said. The watch list also includes separate entries with aliases, fake passports and fake birth dates, bringing the total number of records to more than 1 million, he said.

TSA spokesman Christopher White said the agency’s “no-fly” watchlists to screen travellers were “scrubbed” last year to remove about half of the names, leaving them with somewhat fewer than 50,000.

He said Kennedy and Lewis were never on the list, and that problems they reported were due to their misidentification with names properly on it.