MOSCOW: In the most high-profile killing of its kind, Ukraine’s SBU intelligence service assassinated the chief of Russia’s nuclear, biological and chemical protection troops, in a bomb blast outside an apartment building in Moscow on Tuesday. Lieutenant General Igor Kirillov, who was accused by Kyiv of being responsible for the use of chemical weapons against Ukrainian troops, was killed along with his assistant when a bomb hidden in an electric scooter went off, Russia’s Investigative Committee, which probes serious crimes, said. An SBU source confirmed to Reuters that the Ukrainian intelligence agency had been behind the hit. “The liquidation of the chief of the radiation and chemical protection troops of the Russian Federation is the work of the SBU,” the source said. The source said a scooter containing explosives was detonated, killing both Kirillov and his aide, as they stepped out of a building in Moscow. Unverified video footage of the attack circulating on social media showed two men exiting the building to get into a car followed by a large explosion as the two men remained on the pavement. Reuters could not independently verify the footage. Kirillov, 54, is the most senior Russian military officer to be assassinated inside Russia by Ukraine and his murder is likely to prompt the Russian authorities to review security protocols for the top brass. Former president Dmitry Medvedev, now a senior Russian security official, was cited by the state RIA news agency as saying that Ukraine’s leadership now faced imminent revenge for Kirillov’s murder. Russia denies the Ukrainian allegation it used chemical weapons on the battlefield and Kirillov, who was married with two sons, was himself sometimes shown on state TV giving briefings in which he accused Ukraine of violating nuclear safety protocols or the West of various crimes. Maria Zakharova, a spokeswoman for Russia’s foreign ministry, paid tribute to Kirillov, saying he had worked “fearlessly” for “the Motherland” to expose what she said were the West’s chemical weapons-related and other crimes and what Moscow says were cover-ups in Syria and elsewhere. Russia’s radioactive, chemical and biological defence troops, known as RKhBZ, which Kirillov commanded, are special forces who operate under conditions of radioactive, chemical and biological contamination and who are tasked with protecting ground forces operating in extreme conditions.