Ukraine's security service on Tuesday claimed responsibility for killing the head of Russia's chemical, radiological and biological weapons unit, Lt. Gen. Igor Kirillov.

The Security Service of Ukraine (SBU) was behind the detonation of an explosive device planted in a scooter next to the entrance of an apartment building in Moscow, according to a Ukrainian source briefed on the matter within the who asked for anonymity because they are not authorized to speak publicly about sensitive operations.

A top Russian general accused by Ukraine of being responsible for the use of chemical weapons against Ukrainian troops was assassinated in Moscow by Ukraine's SBU intelligence service on Tuesday morning in the most high-profile killing of its kind.

Lieutenant General Igor Kirillov, who was chief of Russia's Nuclear, Biological and Chemical Protection Troops, was killed outside an apartment building along with his assistant when a bomb hidden in an electric scooter went off, Russia's Investigative Committee, which probes serious crimes, said.

Ukraine’s Security Service (SBU) was behind the assassination of Russian General Igor Kirillov, multiple media outlets reported on Tuesday, citing anonymous sources in the agency.

Kirillov, the commander of the Russian Radiological, Chemical, and Biological Defense Forces, was killed by an explosion, along with his aide, in southeastern Moscow early on Tuesday. The murder took place hours after the general was accused by Kiev of being linked to the use of chemical agents on the battlefield, a claim Moscow denies outright.