The fight at the Illinois Department of Human Services office in East St. Louis was captured on video.
At one point, the video shows two women grabbing each other while a third punches one of them on the back of the head. At another point, a woman walks across the office and punches another person in the face.
It took several minutes for security officers to separate the group and restore order. Some of the people involved in the fight initially refused to leave.
The nearly three-minute video, which contains explicit language, was posted on YouTube.