A flag-burning protest outside the Republican National Convention in Cleveland Wednesday turned into a melee when officers waded into the crowd to put out a man who accidentally set himself and others on fire.

Two officers were assaulted during the action and 17 protesters were arrested on a variety of charges.

Los Angeles Times reporter James Queally tweeted that officers only converged on the demonstration once a protester's pants caught on fire and not because of the flag burning.

One of the officers can be heard on a cellphone video telling one of the protesters, “You’re on fire, stupid,” after being challenged as to why the officers were interfering with the protest.

The group behind the flag-burning protest disputed the police account of what happened and demanded its members be released, the International Business Times reports.

Joey Johnson, a member of the Revolutionary Communist Party who was party to a U.S. Supreme Court case that legalized flag-burning, was among those taken into custody after the chaotic scene Wednesday afternoon near a security entrance to the Quicken Loans Arena. Cleveland Police Chief Calvin Williams said Johnson was the protester who set himself on fire on while lighting up the flag, forcing police to intervene.