Airline passengers were grounded at Newark Liberty International Airport for about six hours Sunday night when a man bypassed security by walking through a checkpoint exit into the secure side of a terminal.
Authorities were still searching for the man early Monday morning.
Transportation Security Administration spokeswoman Ann Davis says the man walked down an exit lane at Terminal C, which is used by Houston-based Continental Airlines Inc. Screening was halted while air safety authorities looked at surveillance tapes to try to identify the man.
Passengers were taken from the secure side of the terminal to the open side to go through screening again.
The terminal was searched thoroughly to make sure no dangerous objects were in it before the security checkpoints reopened around 11:45 p.m., the TSA said. The man wasn't found, but the TSA said its re-screening effort ensured every passenger was fully screened.
Alison Day, of York, England, was supposed to leave for Manchester, England, at 7:30 p.m. She was traveling with a party of seven including an 18-month-old and a 5-year-old.
"I'm not angry that this is happening, but I'm angry that there was a lack of organization," she said.
She said her party, headed home after a Caribbean cruise, was escorted out of Continental's lounge but given no further instructions.
Continental spokeswoman Susannah Thurston said it was an airport security issue not involving the Houston-based airline.
The Port Authority of New York and New Jersey, which runs area airports, assisted the TSA following the possible security breach.
Also Sunday, the TSA said passengers flying into the United States from nations regarded as state sponsors of terrorism and countries of interest will be subject to enhanced screening techniques, such as body scans and pat-downs.
Starting Monday, all passengers on U.S.-bound international flights are subject to random screening.
The Department of State lists Cuba, Iran, Sudan and Syria as state sponsors of terrorism. The other countries whose passengers will face enhanced screening include Afghanistan, Algeria, Iraq, Lebanon, Libya, Nigeria, Pakistan, Saudi Arabia, Somalia and Yemen.
A Nigerian man accused of trying to set off an explosive device aboard a U.S. airliner on Christmas Day has told investigators he received training and instructions from al-Qaida operatives in Yemen.