WASHINGTON (CNN) -- About a hundred times a day, from anywhere in the world, a phone call comes in that sounds something like this: I think I've got a terrorist suspect here, can you check it out?
Analysts reportedly handle about 100 calls daily at the Terrorist Screening Center in northern Virginia.
Answering those calls are dozens of operations specialists in a highly secure center in a classified location in northern Virginia. With access to the government's secret terror watch list, their job is to make sure nobody on the list falls through the cracks.
CNN got a firsthand look inside the Terrorist Screening Center recently -- but not until a security officer who accompanied the TV crew at all times bellowed to the hub of the center's operation, "Unsecure!" to make sure any classified information was protected from view.
For the first time publicly, officials told CNN the consolidated watch list has 300,000 names.
Previously, the government had confirmed the center's database had 700,000 records, explaining that one person could be listed by several names or aliases. Watch analysts working in the Terrorist Screening Center »
The center's director, Leonard Boyle, said about 5 percent of the names on the list are U.S. citizens.
The procedure goes something like this. If a law enforcement or security officer working at a border crossing or an airport or making a traffic stop runs the name of a person through a computer and gets an initial positive hit, he calls the Terrorist Screening Center, where an analyst determines whether the person stopped is indeed on the terror watch list.
The analyst then questions the caller further to find out details about the suspect and uses information on the center's database to make a determination.
The majority of calls to the center come from border agents, Boyle said.
"Unlike prior days when that agent at the border would have access to a limited amount of material, he or she now has access to the entire intelligence community and law enforcement's database as to who might represent a threat," Boyle said.
Sixty-five percent of the names are confirmed matches, Boyle said.
Officials said the 4-year-old center and its watch list are key weapons in protecting the nation's safety. The center is staffed 24 hours a day, seven days a week by FBI personnel, along with others on loan from various government agencies.
Twelve watch lists from throughout the government have been consolidated into one master document. The names are persons whom the government has determined there is a reasonable suspicion of being associated with terrorism.
After the terror center confirms a name on the list, the inquiring agent "can drill down deeper and get more information about that person and make a more informed decision as to whether he represents a threat to the people of the United States," Boyle said.
If there's a warrant against the person or an immediate threat is cited, he or she is taken into custody. If the person is trying to enter the country, oftentimes a border agent will just deny entry.
Many individuals are simply let go, and agents update intelligence files with any information gleaned from the latest encounter. The final decision rests with each individual security agency such as the Transportation Security Administration or the FBI.
The center has come under criticism on several fronts.
A recent Justice Department inspector general's report said of 105 watch list records examined in an audit, 38 percent contained errors or inconsistencies; the center operated two versions of its database, but some information was not found in both; and the names of 20 known or suspected terrorists were not made available to all of the nation's frontline screening agents.
Officials defended their record and said the problems are being fixed.
"It is not as though 20 records simply went missing and people could have entered the country," Boyle said. "There are backup and redundant systems that would have allowed many of those persons to have been identified if they did in fact try to get into the country. We now do a daily reconciliation to make sure that every record that comes into the screening center each day is properly listed and exported that same day."
Members of Congress said more improvement is necessary.
"The system is still choking on an awful lot of inaccurate data," said Sen. Ron Wyden, D-Oregon, a member of the Senate Select Committee on Intelligence. "And in my view in too many instances known or suspected terrorists and information about them is falling between the cracks. That's unacceptable, and it needs to be changed so as to protect our country."
Other complaints come from people who said they are repeatedly stopped for questioning when traveling because their names are similar to those on the list or are wrongly listed.
The American Civil Liberties Union has filed a class-action lawsuit, including almost a dozen such people.
Boyle said the center is working to improve the situation.
"We have a dedicated staff who do nothing but work to redress matters," he said.
However, he cautioned, "It is a time consuming and thorough process" that must be followed to make sure wrong names are not removed. E-mail to a friend