Russian general in charge of radiation, chemical and biological protection forces has been killed in an explosion in Moscow, the country’s investigative committee has said. Lt Gen Igor Kirillov was killed outside an apartment building on Ryazansky Prospekt, which starts 7 km (4.35 miles) south-east of the Kremlin. The explosion was caused by a device hidden inside an electric scooter, according to the committee.

Kirillov’s assistant also died in the blast, which was triggered by an explosive device placed in a scooter, officials said. Russian investigators have opened a case into the two deaths, the committee’s spokesperson Svetlana Petrenko said.

Sources in Kyiv have confirmed that Ukraine’s SBU carried out the killings in Moscow.“We were involved in the operation,” the source told the Guardian.

Dmitry Medvedev, deputy chairman of Russia’s Security Council, said on Tuesday that the Ukrainian leadership would face imminent revenge for the killing of a top Russian general, RIA news agency reported. “Realising the inevitability of its military defeat, it launches cowardly and despicable strikes in peaceful cities,” he said.