Armen Sarkisian, a known mafia boss from east Ukraine, is the latest target in a string of explosions on Russian soil.

In December, Ukraine took credit for the killing of Russian General Igor Kirillov in a bomb blast outside a Moscow apartment building. There was no immediate comment from Ukraine.

while another drone hit a building under construction in the Moscow City financial district. The third drone was jammed by radio-electronic warfare devices and crashed in the Moscow suburb of Khimki.

The massive drone strike led to a casualty in the city of Ramenskoye in the Moscow region, and reports mentioned the ...