As head of Russia's Radiological, Chemical and Biological Defense forces, Igor Kirillov - who has died in an explosion in Moscow - was accused by the West of overseeing the use of chemical weapons in the field battle in Ukraine.

Sources from Ukraine's SBU security service said that was behind the blast and described it as a special operation against a legitimate target.

Kirillov and an aide were killed by explosives planted in an electric scooter, according to Russian officials, which detonated as he left the building where he lived on Ryazansky Prospekt in the east - south of Moscow.

He had been known for extraordinary briefings at the Russian defense ministry which led the UK Foreign Office to name him as "an important mouthpiece for Kremlin disinfection".

Kirillov was far more than just a legend, heading Russia's Timoshenko Radiological, Chemical and Biological Defense Academy, before going on to lead the Russian military's Radiological, Chemical and Biological Defense Forces there in 2017.

The UK Foreign Office said that the force he commanded had "deployed barbaric chemical weapons in Ukraine", highlighting what he described as widespread use of riot control agents and "numerous reports of the use of the toxic choking agent chloropicrin ".

The night before he was killed, Ukraine's SBU announced that he had been named in absentia in a criminal case for "mass use" of banned chemical weapons in eastern and southern Ukraine.

He announced "more than 4,800 cases of the enemy using chemical weapons" on the territory of Ukraine since the start of the full-scale offensive in Russia in February 2022.

They said toxic substances were used in drone attacks as well as combat grenades.

Kirillov earned his reputation from the beginning of the war with a series of claims directed towards Ukraine and the West, none of which were based on reality.

Among his worst claims was one that the US had been building biological weapons laboratories in Ukraine. It was used in an attempt to launch a full-scale attack on its smaller neighbor in 2022.

He produced documents in March 2022 that he claimed were seized by Russia on the day of the attack on February 24 - which were amplified by pro-Kremlin media but rubbished by independent experts.

Kirillov's notorious accusations against Ukraine continued into this year.

Last month, he said that "one of the main goals" of the anti-Ukrainian offensive into Russia's Kursk border region was to capture the Kursk nuclear power plant.

He presented a slide show, allegedly based on a Ukrainian report, claiming that in an accident only Russian territory would be exposed to radioactive contamination.

One of Kirillov's recurring themes was that Ukraine was trying to develop a "dirty bomb".

Two years ago he said that "two groups in Ukraine have made specific instructions to create a 'dirty bomb'. This work is in the final stage".

His claims were rejected by Western countries as "obviously false".

But Kirillov's claims prompted Ukrainian President Volodymyr Zelensky to warn that if Russia suggested that Kyiv was preparing such weapons, it only meant one thing - that Russia was preparing it. already.

Kirillov returned to his dirty bomb claims last summer, this time claiming that a chemical weapons laboratory had been found near Avdiivka, a city in eastern Ukraine. captured by the Russians last February.

Kyiv, he said, was violating the international Chemical Weapons Convention with a variety of substances supported by Western countries, including the psychochemical warfare agent BZ as well as hydrocyanic acid and cyanogen chloride. .

His death is seen by pro-Kremlin loyalists as a blow, but also as evidence that Ukraine has the ability to target high-profile officials in Moscow.

The deputy speaker of the main house of the Russian parliament, Konstantin Kosachev, described the death as an "irreparable loss".