Russian authorities and news reports say an explosion in an upscale Moscow neighborhood killed two people, including the founder of a battalion that battled Kyiv's forces in eastern Ukraine.

Armen Sarkisyan, the founder of a separatist battalion fighting in eastern Ukraine, died after an explosion in an apartment complex, according to reports citing the Russian authorities.

Armen Sargsyan, the leader of a paramilitary unit wanted by Ukraine, died from his injuries following an explosion on Monday morning.