CHICAGO — Three security officials dragged a passenger from a United Airlines flight at Chicago’s O’Hare International Airport when the man reportedly refused to leave his seat after being asked to deplane because the flight was overbooked.

A statement from United says “Flight 3411 from Chicago to Louisville was overbooked. After our team looked for volunteers, one customer refused to leave the aircraft voluntarily and law enforcement was asked to come to the gate.”

United said it apologized “for the overbook situation.”

One passenger posted the video on Facebook. It shows the guards grabbing then dragging the passenger down the aisle. Screaming is heard and other passengers say “Oh my God” and “Look at what you did to him.”

United said airline representatives chose four passengers at random when no volunteers agreed to leave the overbooked flight. They requested law enforcement assistance when one of them refused to leave.

The passenger who posted the video said United asked for four passengers to relinquish their seats for airline employees on stand-by.