Myanmar authorities have accused the Rohingyas Muslims of killing 28 Hindu villagers whose bodies were found in a mass grave.
The army said the bodies of 20 women and eight men and children were found in two wells in northern Rakhine state.
The state has been in turmoil since August 25 when Rohingiya militants launched deadly attacks on police posts.
More than 400,000 Rohingyas have fled an offensive by the military, which the UN accuses of ethnic cleansing.
Hindus, as well as members of the majority of the Buddhist population in Myanmar (also called Burma) have also been displaced from their homes by violence in Rakhine.
The army denies widespread reports that it has committed atrocities, saying it only addressed those belonging to the Arakan Salvation Rohingya (Arsa) militant army that launched the attacks.