MOSCOW — A 29-year-old Uzbekistan citizen has been detained in Moscow over the killing of top general Igor Kirillov, according to Russia's security service.

Russian state agency TASS reported on Wednesday that the man was recruited by Ukrainian intelligence. On Tuesday, Ukraine's Security Service (SBU), claimed responsibility for Kirillov's death.

Kirillov, the head of the Russian military’s nuclear, biological and chemical protection forces, was killed in an explosion outside an apartment building on Tuesday from a remotely detonated device hidden in an electric scooter.

His assassination came a day after Ukraine’s security service opened a criminal investigation against him, accusing him of directing the use of banned chemical weapons.

An official with the SBU, who spoke on condition of anonymity because they were not authorised to release the information, described Kirillov as a “war criminal and an entirely legitimate target.”

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 US State Department said 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.

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, deputy head of Russia’s Security Council chaired by President Vladimir Putin, described the attack as an attempt by Kyiv to distract public attention from its military failures and vowed that its “senior military-political leadership will face inevitable retribution.”

Some Russian military bloggers and hawkish commentators made unsubstantiated claims that the US could have been involved in Kirillov's killing.

Asked about Kirillov’s death, US State Department spokesman Matthew Miller told reporters Tuesday: “The United States was not aware of it in advance and was not involved.” — Euronews