A senior Russian general was killed Tuesday by a bomb hidden in a scooter outside his apartment building in Moscow, a day after Ukraine's security agency levelled criminal charges against him.

A Ukrainian official said the country's security service carried out the attack. Lt.-Gen. Igor Kirillov, the chief of the military's nuclear, biological and chemical protection forces, was killed as he left for his office.

Kirillov's assistant also died in the bombing, which was triggered remotely, according to Russian news reports. Images from the scene showed shattered windows and scorched and blackened brickwork.

Kirillov was under sanctions from several countries, including the United Kingdom and Canada, for his actions in Moscow's war in Ukraine. On Monday, Ukraine's Security Service, or SBU, opened a criminal investigation against him, accusing him of directing the use of banned chemical weapons.

An official with the SBU told the Associated Press was behind the attack. A similar claim was made by an SBU official to the Reuters news agency.

The SBU has said it recorded more than 4,800 occasions when Russia used chemical weapons on the battlefield since its full-scale invasion in February 2022. In May, the U.S. State Department said in a statement that it had recorded the use of chloropicrin, a poison gas first deployed in World War I, against Ukrainian troops.

Russia has denied using any chemical weapons in Ukraine and, in turn, has accused Kyiv of using toxic agents in combat.

Russia's Medvedev vows immediate revenge

Kirillov, who took his current job in 2017, was one of the most high-profile figures to level those accusations. He held numerous briefings to accuse the Ukrainian military of using toxic agents and planning to launch attacks with radioactive substances — claims that Ukraine and its Western allies rejected as propaganda.

Dmitry Medvedev, ex-Russian president and current deputy chairman of Russia's Security Council, said on Tuesday that the Ukrainian leadership would face imminent revenge for the killing, RIA news agency reported, accusing Ukraine of "cowardly and despicable strikes."

Since Russia invaded Ukraine, several prominent figures have been killed in targeted attacks.

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Darya Dugina, a commentator on Russian TV channels and the daughter of Kremlin-linked nationalist ideologue Alexander Dugin, died in a 2022 car bombing that investigators suspected was aimed at her father.

Vladlen Tatarsky, a popular military blogger, died in St. Petersburg in April 2023, when a statuette given to him at a party exploded. A Russian woman, who said that she presented the figurine on orders of a contact in Ukraine, was convicted in the case and handed a 27-year sentence.

In December 2023, Illia Kiva, a former pro-Moscow Ukrainian lawmaker who fled to Russia, was shot and killed near Moscow. The Ukrainian military intelligence lauded the killing, warning that other "traitors of Ukraine" would share the same fate.

On the battlefield, RIA reported that Russian forces have taken control of the settlement of Hannivka in eastern Ukraine. Reuters could not independently verify the battlefield report.

The Ukrainian air force said on Tuesday it had downed 20 Russia-launched drones.

It said on the Telegram messenger that Russia launched a total of 31 drones and an additional 10 did not reach their targets. One was still in the air.