The Asian Football Confederation said Thursday it was investigating a mass brawl involving two teams in the AFC Champions League.

Punches were thrown and the benches of both sides got involved when Wednesday's encounter between China's Zhejiang and away side Buriram United of Thailand descended into violence.

It was unclear what sparked it, but the chaotic scene erupted shortly after the final whistle of Zhejiang's bad-tempered 3-2 victory.

"The AFC underlines the importance of fair play, mutual respect and sportsmanship, and takes a zero tolerance approach towards all acts of violence which threaten the physical integrity of players and officials," the Asian Football Confederation said in a statement.

"The AFC is investigating the incident(s) but does not comment on ongoing disciplinary affairs, which are matters for the AFC Disciplinary and Ethics Committee and its secretariat to consider."

AFC general secretary Windsor John told AFP that they were waiting for reports from the referee and match commissioner.

Multiple punches and kicks were exchanged between the two teams and at least two players ended up on the floor. One grabbed an opponent in a headlock.

Security personnel raced onto the pitch at Huzhou Olympic Sports Center to restore order.

The bad blood extended into Thursday and the official Instagram account of the Thai team posted pictures of one of their players cowering on the ground.

The caption read: "Is it AFC Champions League? Come to play football or come to the battlefield."

Buriram also posted a photograph of what appeared to be a home fan hurling something from the stands.