Russia’s security service says a 29-year-old Uzbekistan citizen has been detained over the killing of senior general Igor Kirillov and his assistant in Moscow.

Lt Gen Igor Kirillov, head of the Nuclear, Biological, Chemical Defence Forces (NBC), was outside a residential block early on Tuesday when a device hidden in a scooter was detonated remotely.

Russian security services said the suspect was recruited by Ukrainian intelligence, according to state media agencies.

A Ukrainian source told the BBC on Tuesday that the killing was orchestrated by Ukraine’s security service.

The source said Kirillov – who was Russia’s chemical weapons chief – was “a legitimate target” and alleged he had carried out war crimes.

On Monday, the day before the killing, Ukraine charged Kirillov, 54, in absentia, saying he was “responsible for the mass use of banned chemical weapons”.

The Russian Federal Security Service’s (FSB) public relations centre said on Wednesday the detained 29-year-old was “suspected of committing a terrorist attack”.

A statement said that during “interrogation he explained that he was recruited by the Ukrainian special services”.