Inside the Newark Liberty International Airport Monday night, an Alaska Airlines employee spotted two men who she thought looked suspicious.

When the employee approached them, the men started running and she screamed “evacuate,” a source with knowledge of the incident told CNN, based on preliminary information. The yells stirred panic at the gate, the source said.

The concerned employee hit an alarm after talking to the two men and nearly 200 passengers evacuated the gate, Port Authority of New York and New Jersey spokesman Steve Coleman said.

One passenger told CNN affiliate WPIX the experience was “terrifying.”

“Imagine you’re starting to board and a frazzled attendant comes off the plane, stops the process, asks someone to call the police, then starts yelling, with increasing loudness, ‘evacuate!'”

The passenger told the affiliate they ran with the crowds, hid under seats and looked for an exit.

“Sounded like gun shots but after seeing the damage in this terminal, it’s more likely it was glass being shattered from people jumping.”

The airport tweeted later Monday, “it was determined that there was no threat,” adding that all passengers and employees were going to be re-screened for precaution.

The two men were identified and after being questioned by police, were released with no charges, Coleman said. The employee is still being questioned, Coleman added.

“There is no danger to anyone at the airport and the situation is under control,” Coleman said. “The incident is under investigation.”