After a match on Monday against Thanh Hoa FC, Thang went up to assistant referee Nguyen Le Nguyen Thanh and viciously butted him in the face, causing him to lose a tooth.
The organizers said a yellow card does not go far enough, and have reported the incident to the Vietnam Football Federation (VFF) and sought further disciplinary action against Thang.
The official told VnExpress: "Thang assaulted me. I have reported to the V. League organizers and VFF.
"When the game ended, I saw Thang walk towards me, and I thought he wanted to shake hands. But to my surprise, he suddenly said ‘do you want to die?’ and then headbutted me in the face.
"His teammates were about to join him, but fortunately Thanh Hoa players stopped them in time and the police escorted us out safely."
After the game ended, HCMC players and coaching staff accused match officials of unfairly giving Thanh Hoa too much extra time after full-time and a chance to equalize in the dying seconds.
Thanh added: "When the referees gave Thanh Hoa a free kick, HCMC players didn’t react. But after it turned into a goal, they surrounded and attacked us.
"The doctor said I have to replace my tooth."
The league organizers also wanted the VFF to fine Becamex Binh Duong player Nguyen Thanh Thao for kicking a Song Lam Nghe An player in the knee during their match on Monday.