The scuffle began at a news conference to promote a title fight between the two on Sept. 27 at the MGM Grand Garden Arena. During a staredown photo opportunity in the hotel lobby, Cormier shoved Jones backward after the two hit heads.
After regaining his footing, Jones went after Cormier with full-force punches. UFC director of communications Dave Sholler attempted to separate the two, but Jones shoved him aside into the canvas backdrop.
Jones and Cormier then toppled from the stage, nearly falling onto a marble fountain in the center of the lobby. Jones stood over Cormier and continued to throw punches until MGM security managed to separate them.
Cormier was immediately escorted away. Jones stepped back onto the stage, flexed and then screamed loudly three times in front of bystanders who had gathered.
Malki Kawa, Jones' manager, got involved after the two fell from the stage. He was seen pulling Cormier away from Jones in a video.
"This is certainly not a proud moment for the UFC organization," Kirk Hendrick, the UFC's chief legal officer, said according to UFC.com. "We expect more from our athletes, especially these two gentlemen, who are very well-trained and highly educated professionals. Their actions were clearly a violation of the UFC's code of conduct.
"There are going to be ramifications," he concluded. "Whether you're the champion, or this is your first fight in the UFC, there are going to be ramifications from the UFC for these actions."
Jones, 27, was originally scheduled to fight Alexander Gustafsson at UFC 178 on Sept. 27. Gustafsson was forced to withdraw from the bout due to a torn meniscus in his knee.
Cormier and Jones have gone back and forth in the media for years regarding a potential fight. Cormier dropped to light heavyweight from heavyweight earlier this year.
Jones is considered the No. 1 pound-for-pound fighter in the world. He will seek his eighth title defense against Cormier. Moments before the brawl, Jones told ESPN.com it would be an emotional fight for him but that he was confident he would dominate Cormier.
Nevada State Athletic Commission chairman Francisco Aguilar told ESPN.com the commission would have to review video of the incident before providing comment. He did say that licensed fighters in Nevada are asked to exemplify good sportsmanship at all times.
UFC CEO Lorenzo Fertitta declined comment when reached by phone, stating he had not yet seen the video.
Shortly after the fracas, Jones tweeted, "Come on DC where was your takedown defense?" and "Put some ice on that face DC, you got lots of interviews tomorrow."
Jones and Cormier are scheduled to appear at a news conference in Los Angeles on Tuesday.