(CNN) 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.

The employee was a flight attendant and will not be charged in connection with the incident, according to a source familiar with the Port Authority investigation. No other workers were suspicious of the two men, the source said.

One passenger told CNN affiliate WPIX the experience was "terrifying."

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