CHICAGO (CBS) — Passengers might notice extra security when boarding the train during the morning commute on Monday.

In the wake of the terrorist attacks in Paris, the CTA, Metra, Pace, and the South Shore Line were taking extra steps to keep commuters safe.

Although federal authorities have said there is no specific or credible threat to the U.S. related to the attacks in Paris, major cities in the U.S. have gone on a heightened state of alert, and put increased security measures in place.

Local mass transit agencies have increased law enforcement levels, and employees have been told to be vigilant about any suspicious activity.

Commuters can expect to see added security on trains and platforms.

“Unfortunately, it’s just a side-effect of the attacks, and people are afraid,” said commuter Conor Durcin. “I didn’t feel unsafe before … but that’s me. Maybe I’m cavalier about it. Other people’s fears, I think, are justified in a way.”

Commuters have been encouraged to report anything suspicious or unusual to their conductor, or to transit police.