A fight between high school students and what appear to be police officers in Russia’s republic of Chechnya ended in gunshots, Russian media reported Monday.

According to the local Kavkazr.com news website, the scuffle at public school number 54 in Chechnya’s capital of Grozny started as a verbal altercation when a police officer insulted a ninth-grade student. It then reportedly turned into a physical fight when the officer struck the student in the face, after which other students and officers joined the brawl.

Videos published online show a man in a uniform fighting a student as other students gather around. Gunshots can be heard, though it is unclear who fires them.

The fight took place on the day of a state standardized math exam, the Dozhd television channel reported.

Other accounts of the incident say that the men in uniform were security guards and that the fight started after a student was kicked out of his exam for using a cheat sheet.

The regional investigative committee has opened a probe into the incident.