CHICAGO (CBS) — A plane from Kansas landed at O’Hare International Airport Monday afternoon after a report of smoke in the cargo hold.

The Atlas Air 747 landed at O’Hare late Monday afternoon. The plane landed on Runway 28C.

Atlas Air normally operates as a cargo airline – but it also operates as a passenger airline. The Chicago Fire Department confirmed 314 passengers safely exited the plane.  We have since learned the people on the plane were military personnel.

Chopper 2 was near the scene as the Atlas Air flight made its safe landing. Emergency trucks were seen surrounding the plane.

The 314 U.S. military personnel onboard were heading from Topeka, Kansas to Poland. We are told the soldiers were part of the 2nd Armored Brigade Combat Team.

The Fort Riley base troops recently left the base and were heading to Europe. It is not clear what their exact mission was – but we know once the smoke was spotted in the cargo, the 314 soldiers landed in Chicago and evacuated the plane.

No one was hurt, and regular operations continued at O’Hare.

Mechanics checked out the problem, and it is believed the men and women continued on to Poland to carry out their mission.

Atlas Air still cannot pinpoint what caused the smoke – but the airline said the aircraft would only return to service if they deemed it safe.

This was the full statement from Atlas Air:

“We can confirm that Flight 5Y8380 landed safely after receiving an indication of a potential abnormality in the cargo compartment soon after departure from Topeka, Kansas (FOE).  The crew followed all standard procedures and safely diverted to Chicago, Illinois (ORD).  As a precautionary measure, Chicago authorities inspected the aircraft upon arrival and determined the aircraft was safe for all passengers to de-plane.  Our team is investigating the cause of this incident and will work to safely return the aircraft to service.”