Four people have been injured after a student armed with a knife stormed his school in the Republic of Bashkortostan in Russia’s Urals, and attempted to set it on fire, officials said.

The incident took place on Wednesday morning in Sterlitamak, the second-largest city in the republic. “According to our information, four injured people, including three children, were transported to a hospital in Sterlitamak,” Russia’s Health Ministry has confirmed.

A 17-year-old boy was armed with a knife and attempted to set fire to the school after attacking several people inside a classroom. The attacker “entered the Computer Science class” and attacked a female student and a teacher with a knife, Russia’s Investigative Committee said in a statement. He then ”poured out a flammable substance,” set it on fire, and tried to commit suicide. When the fire alarm went off, one of the students from a nearby class jumped from the window out of fear.

“Some guy was running in school with a knife. The teacher held the door, then ran into the class. [He] stabbed a girl, and she jumped from the second floor,” a witness to the incident told bashinform.ru.

A video purportedly showing the aftermath of the incident has emerged online. The footage shows students being evacuated from a school building where the incident reportedly took place. RT has yet to verify the content.

Medics, rescue personnel and police are currently working in the scene. The Investigative Committee confirmed to Interfax that it has sent its specialists to probe the incident in Sterlitamak.

A number of similar incidents have taken place in Russian schools in recent months. At least a dozen people were injured at a school in the city of Perm in January, after an 11th grader and a former student entered the building armed with knives, and attacked a female teacher and students. Also in January, a student armed with an ax stormed a school in the Siberian city of Ulan-Ude and used a Molotov cocktail to set the building on fire.

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