Maoists blew up a vacant school building in Latehar district, police said today.
About 20 Maoists went to the middle school and packed explosives before triggering the blast last night at Newari village.
There was no casualty in the blast, which took place on the eve of the third of the five-phase elections for 11 seats in Jharkhand today.
Elections in Latehar district will be held in the fifth and final phase of polling on December 18.