DALLAS (AP) - More than two dozen full or partial evacuations at Dallas-Fort Worth International Airport have reportedly resulted from security blunders, false alarms and communication breakdowns since the East Coast terror attacks.

Changes in security protocol at the airport, one of the nation's busiest, were instituted after the evacuations which delayed tens of thousands of travelers and cost airlines and airport vendors millions of dollars but were not triggered by any credible threats, officials say.

The Transportation Security Administration's federal security director at DFW Airport acknowledged the fledgling agency has made mistakes during the 13 months it has been responsible for security.

"We're always going to err on the side of security," the TSA's Jimmy Wooten told The Dallas Morning News in Monday's editions. "With these incidents, though, we, one, needed to find out what went wrong and, two, find out how to fix it."

Since the changes, however, the airport recorded only one minor security-related evacuation in the last four months. Wooten said the reduction in evacuations is due in part to greater sophistication and better communication among the more than 1,250 TSA screeners and the airport's police force.

Changes ranged from retraining screeners to buying cell phones and pagers for supervisors. The airport board recently approved a $5.7 million plan to install video cameras to defend against security breaches at emergency exit doors, which accounted for half of the evacuations.

The TSA said DFW Airport was tied for third nationwide as of September for the most evacuations since the terrorist attacks, with five. The agency defines evacuations as incidents in which officials had to shut down a significant section of a terminal or the entire building. Updated rankings to include the most recent evacuation on Oct. 10 -- DFW Airport's sixth by TSA's count -- were not available.

Security officials partially or completely evacuated terminals 25 times dating to Sept. 11, 2001, when a combination of private screening companies, the National Guard and Federal Aviation Administration guarded checkpoints, DFW airport records show. Media reports and interviews with airport officials confirmed two additional evacuations, with 10 of the incidents occurring overnight.

Airport officials said 20 of the 27 evacuations occurred after the TSA assumed screening responsibilities in September 2002. One of the six evacuations counted by the TSA does not appear in DFW Airport records, with TSA officials saying a Feb. 18 evacuation occurred overnight with an open fire door, causing "little impact" on operations. Airport officials said there was a problem with a fire door but no evacuation.