NEWARK, N.J. (CBSNewYork) — A scare at Newark Liberty International Airport sent passengers running from terminals onto the tarmac Monday.

People ran, fearing there was an active shooter or bomb threat at the airport. But it turned out to be nothing close to that, CBS2’s Hazel Sanchez reported.

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Passengers were evacuated from a terminal after a security breach.

Police said a passenger exited through a security door at the Terminal C, which is used by United, and set off an alarm. That passenger was arrested.

People posted pictures on social media of the terminal as it was being evacuated.

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They also posted pictures of planes that were stopped on the tarmac and passengers being rushed back into a safe area of the airport.

A woman who works at the terminal said it was terrifying.

“I think people saw people running and it was more so word of mouth that everyone found out that they needed to hide. Some of my coworkers hid in planes, some where hiding in kitchens, some in bathrooms. Everyone was just hiding. It was terrifying,” Belinda Pena said. “At first we heard it was a crazy lady, and then we heard it was a fight broke out, and then we heard it was an active shooter/bomb threat, and we were like, ‘What’s happening?'”

All passengers had to be rescreened before boarding.

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Port Authority police said service is back to normal.