Updated

Federal transportation officials say a security officer at O'Hare International discovered a firearm during an x-ray screening and a passenger was taken into custody.

The Transportation Security Administration did not name the passenger. But the Cook County State's Attorney's office said Illinois state Sen. Donne Trotter was charged with a felony Wednesday for allegedly trying to board a flight with a weapon. Chicago police said Trotter was traveling from O'Hare to Washington D.C. with the weapon and ammunition in a carry-on bag.

TSA officials say the agency notified the Chicago Aviation Police Department, which took control of the firearm.

Messages left for Trotter on his cellphone and at his office in Chicago seeking comment weren't immediately returned. He is expected in Cook County bond court on Thursday.