More than 50 heavily armed rebels stormed into the remote Markapadar village in Khairput block of the district and blew up the two adjacent buildings using powerful landmine.
The Maoists then disappeared into the nearby forest shouting slogans against the government and security forces, the police said.
The attack is part of a strategy by the rebels to destroy buildings being used to accommodate central para-military forces for carrying out anti-Maoist operations in the region.
As many as eight panchayat and four school buildings, besides several government structures, have been destroyed by the ultras during the past about four months in Malkangiri district, the police added.