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.

Since the start of Russia’s invasion, Ukraine has been accused of orchestrating a series of lethal operations on Russian territory.

After an explosion in Moscow that killed the founder of a unit fighting on Russia’s side in the war against Ukraine, speculation swirled around two potential explanations: A turf war and a Ukrainian assassination.

An explosive device reportedly detonated in the entrance of a Moscow apartment complex on Monday morning, injuring multiple people and killing the head of a Russian paramilitary unit. The incident echoes the December death of Russian chemical weapons chief Igor Kirillov,

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

Armen Sarkisyan has been described as a "crime boss" by Ukraine's SBU intelligence service. It said he was suspected of participating in and aiding "illegal armed groups" and had formed a pro-Russian military unit made up of local convict fighters.