The leader of the pro-Russian paramilitary group, Armen Sargsyan, has died in hospital.
This comes after the Arbat battalion founder was injured in an explosion in Moscow earlier this morning.
Sargsyan was severely injured following a blast in the entrance hall of a residential building in north-west Moscow, 12km from the Kremlin.
He was evacuated to a hospital by helicopter and placed in intensive care after the explosion.
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However, the 46-year-old eventually succumbed to his injuries and gave up the ghost.
Kyiv had accused Sargsyan of helping Russian forces in their war effort.
Meanwhile, in December, the Ukrainian security service, SBU, said Sargsyan was a suspect in recruiting prisoners to fight in Ukraine.
The SBU added that Sargsyan was part of the inner circle of fugitive former Ukrainian President Viktor Yanukovych.