A Ukrainian shell that reportedly hit the border town of Donetsk could have "irreversible consequences", Russia's foreign ministry has warned.
According to Russian news agencies, the shell hit a residential building, killing one person and injuring one other.
Russia said the fatality was the result of an "aggressive act" against sovereign Russian territory and against Russian citizens.
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Arthur Simpson-Kent, 48, admitted killing Ms Blake and their sons according to his lawyer.
Two brothers have been arrested on suspicion of murder after their parents were found dead in their own home over the weekend.
The first man to be convicted of murder on the basis of DNA evidence should be moved to an open prison, according to the Parole Board.