Russian police are investigating whether three school attacks this week are connected after a teenager attacked a class with an axe and Molotov cocktail in the Buryatia region.

Five seventh-graders and their teacher were wounded on Friday when a ninth-grader in Buryatia's capital Ulan-Ude, near Lake Baikal in Siberia, attacked them and burned the classroom, according to the investigative committee. One student was in critical condition.

The young man was detained and hospitalised after he tried to commit suicide, it said.

The instructor involved, Russian language and literature teacher Irina Ramenskaya, told Mash, a popular news channel on the Telegram messenger app, that she had been holding a class when suddenly the door opened and an object was thrown into the room. She was struck in the head, she said, and the room began to fill with smoke.

“I started to take the kids out. When I came out, I saw that a person was just chopping the kids with an axe,” she said. “I brought them back in the classroom, where everything was burning. I was bleeding. Before my eyes stood Anton with an axe.”