Russian investigators in part of eastern Ukraine controlled by Moscow said late on Monday that they had detained two soldiers on suspicion of killing a family of nine people, including two children.
The statement said the soldiers were from a region in Russia’s far east and that the reason for the murders appeared to be some kind of personal conflict.
The killings took place in Volnovakha, an industrial town between Donetsk and Melitopol.
Russian media reported that the murderers had used machine guns with silencers to kill the family at night.
Ukraine’s prosecutor’s office said in a statement that it had also begun investigating the crime.