This was reported by the Kazinform agency.
It is noted that as a result, two tenth-graders and one ninth-grader were injured.
Two victims were hospitalized, one was treated on the spot.
The attacker was detained, according to preliminary data, he is on a psychiatric register.
Earlier it became known that in Khimki a fifth-grader with stab wounds was hospitalized from a school.
The governor of the Moscow region Andrey Vorobyov, as reported by the 360 TV channel, visited the girl in the hospital.
According to him, the situation was a shock for everyone, but thanks to the doctors, the schoolgirl regained consciousness.
It is noted that the fifth grader lost a lot of blood.