Policemen patrol on a square in Makhachkala, capital city of the Dagestan Republic, Russia, June 24, 2013. (Xinhua/Jiang Kehong)
MOSCOW, April 24 (Xinhua) -- At least one student was killed and 11 others were injured when a grenade went off in a school in south Russia's Republic of Dagestan on Monday, the regional Interior Ministry said.
The casualties were caused by the reckless handling of the grenade, which was brought to a computer class by a student, according to the ministry.
Ten of the injured have been hospitalized, with three of them in critical condition.
The student who took the grenade to the school has been detained and is being interrogated for where he got the weapon and why he brought it to school.
Dagestan is a hotbed of insurgency in the North Caucasus close to the conflict-ridden Middle East. Repeated violent attacks have plagued the region for years.
But it is still unclear whether Monday's blast was just an accident or linked to terrorism.