Editor’s Note: Digital previously identified Lt. Gen. Igor Kirillov as the head of Russia’s Nuclear, Biological and Chemical Defense Forces, but has revised his title to commander of Russia’s chemical, biological and radiation defense forces.

Lt. Gen. Igor Kirillov, commander of Russia’s chemical, biological and radiation defense forces, and his aide perished in an explosion on Tuesday, a day after Ukraine’s Security Service filed criminal charges against him.

According to the Associated Press, Russia’s Investigative Committee stated that a remotely detonated explosive device, planted on a scooter near a residential building on Ryazansky Avenue, caused the explosion.

The Russian state news agency Tass reported the bomb’s explosive yield was approximately 300 grams of TNT.

Reuters reported that Ukraine’s Security Service (SBU) claimed responsibility for the attack. Digital has contacted the intelligence agency for verification.

“Investigators, forensic specialists, and operational units are working at the scene,” RIC spokeswoman Svetlana Petrenko stated. “An investigation is underway to determine all aspects of this crime.”

Petrenko also classified the explosion as a terrorist act.

Kirillov was indicted by the SBU on Monday for alleged battlefield use of chemical weapons. The AP reported that several nations had already sanctioned him for his role in the war against Ukraine.

The SBU reported documenting over 4,800 instances of chemical weapons use since the war began in February 2022.