CHICAGO (WBBM) – Two off-duty U.S. marshals shot a man in the northwest side Logan Square neighborhood Friday night.

The shooting, at about 7:25 p.m., occurred on the 2100 block of N. Milwaukee Av., according to Chicago Fire Dept. spokesman Larry Langford.

Chicago Police News Affairs Officer Veejay Zala said that two off-duty U.S. marshals first spotted a man with a gun running after several other people on the 2100 block of North Bingham Street. Zala said the marshals also gave chase, and said that when the marshals announced who they were, the man allegedly turned and pointed the gun at them. At that point, fearing for their safety, the marshals fired on the gunman.

Langford said the gunman was wounded in the upper right leg. Paramedics stabilized him and transported him in serious to critical condition to Illinois Masonic Hospital.

No other shots were fired, Zala said.

U.S. Marshal’s Service Chicago district spokesperson Belkis Cantor said when a U.S. marshal is involved in a shooting, a supervisor is called to the scene to take possession of the weapon that was fired, and a full investigation is mounted. Unlike Chicago Police-involved shootings, the marshal in question is not necessarily reassigned pending completion of the investigation.

Zala said Chicago Police will conduct the criminal aspect of the investigation to determine what charges are warranted.

The age of the gunman is unclear. Langford said the wounded gunman is 18; Zala said he is 20.