Armen Sarkisyan, founder of a battalion fighting Ukrainian forces, was targeted in what is being described as an assassination.

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.

An east Ukrainian crime boss and separatist wanted by Kyiv was killed with one other person in a blast at a luxury residential complex in Moscow on Monday, Russian media reported. Armen Sarkisian ...