New York (CNN) -- A security breach at the Newark, New Jersey, airport over the weekend was caused by an officer of the Transportation Security Administration who left his post unattended, an agency spokeswoman said Thursday.

Security video shows the officer walking away from his post at Newark Liberty International Airport, about four minutes after he asked an unidentified man in a light-colored jacket to stay behind the rope line.

Moments later, the man ducks under the rope and walks the wrong way through security to greet a woman, prompting a security breach that shut down Terminal C for hours and forced the rescreening of thousands of passengers.

"The surveillance video from Newark Liberty Airport clearly shows that a TSA officer's actions led to the Sunday incident," spokeswoman Ann Davis said. "We will use this hard lesson to reinforce the sharp focus and tight discipline at all our stations across the country and ensure we maintain the public trust."

The TSA officer was reassigned to nonscreening duties Monday after the incident, which occurred at Terminal C about 5:20 p.m. ET Sunday. The unidentified man walked through an exit on the public side to the secure "sterile" side, TSA said.

Earlier, a Homeland Security official told CNN that the TSA officer was distracted because "a passenger was asking for directions or something." The official said it's not uncommon for TSA employees to get "peppered with questions from passengers every day."

On Tuesday, the TSA officer was placed on administrative leave, the TSA said. Davis has said the agency takes "full responsibility" for the incident.

She told CNN that a passenger notified a TSA officer Sunday afternoon about a person who he believed had walked through the wrong way at a security exit. The passenger could not provide a description of the person, Davis said.

In an attempt to confirm the breach through videotape captured by TSA-funded and Port Authority-installed-and-operated cameras, TSA officials realized the cameras were running but not recording.

TSA officials then scrutinized security tapes recorded by Continental Airlines' cameras and confirmed that an "Asian male" had breached security, Davis said. The TSA was unable to locate the man.

Sen. Frank R. Lautenberg, D-New Jersey, who requested the release of the Continental surveillance video, called on the man to turn himself in to authorities, saying, "You've committed what essentially is a crime."

"He committed a terrible, terrible offense, and he has to pay a price ... that relates to the havoc and the discomfort he caused this place," Lautenberg told reporters at the airport Thursday night.

Davis said earlier this week that although authorities were unable to locate the man, any threat he may have presented was eliminated "by rescreening everyone and recombing the airport to make sure he didn't introduce anything to the environment or hand anything off to anyone."

The incident caused arrival delays, mainly affecting Continental Airlines, the airport's largest tenant. After meeting with the Port Authority about the breach, the TSA has volunteered to check the cameras daily to ensure they are recording, Davis said.

Newark was one of the airports from which the 9/11 hijackers departed.

CNN's Susan Candiotti and Ross Levitt contributed to this report.