Map of Dagestan
At least one teenager was killed and 11 others injured in a blast in Russia's Republic of Dagestan, where an explosion at a local school was reportedly caused by a grenade brought into the building by one of the students.

At least three of the injured teenagers are in a critical condition, RIA Novosti reported, citing a local hospital.

Dagestan's Interior Ministry spokesman confirmed the numbers of the dead and injured to RT.

The incident happened in the village of Agvali, Dagestan, in Russia's North Caucasus region.

A grenade exploded in a computer classroom, RIA Novosti cited the Agvalinskaya school principal, Shamil Abakarov, as saying.

The weapon was allegedly brought into the building by an eighth-grade student, he said.

The ministry confirmed that the student who brought the grenade had been detained.

Investigators are now working at the scene, the official said, adding that anti-terrorist committee is not involved in the case. According to preliminary data, the incident happened due to "careless handling of a weapon," he told RT.