Sources said the militants lobbed the grenade inside the premises of Jim Higher Sceondary School at Sangaiporou at the outskirts ofImphal late last night.
Non-payment of monetary demand from the school authorities could be the reason, sources said adding that no individual or organisation has claimed responsibility.
In another development, Northern Valley Stone Crushers Welfare Association today organised a sit in protest at Koirengei area in Imphal west district against the monetary demand of Rs. 50 lakh made to some individual stone crushers by some militant outfits, a spokesman of the association said.
Published 28 April 2011, 08:32 IST