Video images from the scene of the attack, per Russian news, as reported by the AP, show glass and burn marks on the building. Ukraine's Security Service, called the SBU, said that they were behind the attack on Kirillov. They provided video to the AP showing two men leaving the scene ahead of an explosion.
An official speaking anonymously said that Kirillov was a "war criminal and an entirely legitimate target" due to his alleged use of chemical weapons that have been banned, such as chloropicrin, a gas that was first used during the first World War.
The SBU had "leveled criminal charges against" Kirillov over the use of "banned chemical weapons" just the day before the attack, the AP reports. Kirillov was also under sanction from the UK and Canada over his actions in Russia's war in Ukraine.
Russia claims that they have not used these chemical weapons and has instead accused Ukraine of using them. Russia's Dmitry Medvedev, deputy head of Russian's security council, said that the attack was an effort by Ukraine to distract the public from their wartime losses. Medvedev said that Ukraine's "senior military-political leadership will face inevitable retribution" for the killing of Kirillov. The incident is considered an act of terrorism.
Kirillov is just the latest key Russian believed to have been assassinated by Ukraine. The others include Darya Dugina, who was a Russian pundit. The attack that killed her, authorities believe, was intended for her father Alexander Dugin. Vladlen Tarasky was killed by an explosive statuette at a party and a woman who said she gave him the gift on orders from a Ukrainian contact was convicted in his murder.
Illia Kiva, a Ukrainian who backed Moscow, was killed in 2023 while Sergei Yevsyukov, the former head of a prison where Ukrainian prisoners of war were kept until it was blown up, was killed in December.
