The central terminal area at Los Angeles International Airport was closed for more than 90 minutes Sunday night after "loud noises" let to reports of an active shooter.

Los Angeles Police Department spokesman Andy Neiman confirmed shortly before 10 p.m. that no shooter had been found. Airport police said a man in a Zorro costume had been detained, but it was not clear whether he had any connection to the alert.

All terminals and roads into the airport had been reopened by 11 p.m. PDT, about two hours after the initial reports, officials said. But massive backup faced travelers in their cars and in security lines. Passengers who fled had to be rescreened through security.

When the incident began, scores of people could be seen running from the terminal out on to the sidewalks and streets as police with rifles out stormed terminals. Many other evacuees were standing on the airport tarmac, and abandoned bags littered some sidewalks.

"NBC Nightly News" anchor Lester Holt was arriving in Los Angeles on a red-eye flight when the panic started.

Anne Dudek of Santa Monica, Calif., told the Los Angeles Times that she was going down the escalator to baggage claim in Terminal 7 when a man ran past her and warned everyone to run because people were being shot. 

"People started dropping bags and running out of the terminal," she said. "Panic spread."

"We were on the jetway and someone starts pushing behind us," Jon Landis, a sales representative from Boston who was boarding a flight home, told The Associated Press. "One man was frantic saying there was a shooter."

Police officers, including one with a shotgun, eventually led passengers out of the terminal, through a security gate, and into a parking lot -- where several hundred waited for the terminal to reopen. Ninety minutes after the scare, Landis said he was still waiting for word on his flight.

Passenger Scott McDonald said he was getting off a plane in the middle of the incident and was told by the crew to get back on.

He said looking out the window he could see many evacuees gathered out on the tarmac, a strange sight even for someone who travels almost constantly.

"I've never seen passengers, just normal people, on the tarmac anywhere in the United States," McDonald told KCAL-TV.

Douglas Lee, who was traveling home to Albuquerque with his wife and son, said the greatest danger was being trampled.

"You can imagine hundreds of adults trying to go through an exit door," he explained. At one point, he said he picked up his young son left their luggage.

Corey Rosenbusch was relaxing inside a terminal club on a layover flight from his home in Washington, D.C., to Sydney, Australia, when the lights went off and the staff told everyone to shelter in place.

"People immediately started looking at social media, where they saw reports that there was an active shooter," Rosenbusch told the AP.

He said several officers, including some with assault rifles, led the group out of the area.

Sunday's incident came just days after another false alarm led to a panicked evacuation of Kennedy Airport in New York.

In that incident, police were investigating whether an overly boisterous celebration of the Olympics on Aug. 14 led to noises that were misinterpreted as gunfire, with the ensuing chain reaction turning into a panic as crowds ran to evacuate.

The Los Angeles airport had an actual shooting in November 2013, when a man opened fire in the terminal, killing a security agent and wounding three other people.

The Associated Press contributed to this report.