A Denver Broncos fan is seen viciously attacking an NFL security guard in shocking footage from their game against the Kansas City Chiefs on Sunday.
A video circulating on social media initially shows two male spectators fighting at Kansas City's Arrowhead Stadium as a chaotic brawl breaks out in the stands.
Yet as a stadium staffer attempts to apprehend one of the men involved, who appears to be wearing a Broncos jersey, another Denver supporter flies in and throws two punches at the staff member, the second of which knocks him to the ground.
Multiple crowd members then look to break up the situation when the violent fan grabs the staffer and falls with him to the ground.
DailyMail.com has reached out to the Denver Broncos, the Kansas City Chiefs and the NFL for comment.
More to follow.
An NFL security guard was viciously attacked by a Denver Broncos fan in a chaotic brawl