CHICAGO — A man is in critical condition after he was shot on a CTA Red Line platform overnight.

Police were called to the Garfield Red Line stop around midnight Thursday. According to a CTA spokesperson, video shows an argument between two groups that escalated into a shooting on the platform.

The man was transported to University of Chicago Medical Center where he is listed in critical condition.

The Red Line train was shut down between 63rd and 95th street.

CTA told WGN the Red Line trains will now operate on the same track between 79th and Garfield but did not give any details on the incident.

There was no additional information provided and police are investigating the incident.

No one is in custody.