Marik said a police team led by the Malkangiri superintendent of police rushed to the spot inside Tandiki jungle, 25 km from Malkangiri, following intelligence inputs.
A gun battle ensued between police and Maoists, in which the three were killed.
Marik said several sophisticated weapons were recovered from the dead Maoists.
Police sources said one INSAS rifle and one self-loading rifle were seized from the spot.
The details of Maoist casualties would be clear after a search operation was conducted in the area, sources added.
As the Maoists are observing martyrs' week from Tuesday, security forces have mounted vigil in Maoist-infested districts and holding combing operations at regular intervals.