According to Telegram channels close to the Russian security forces, an explosive equivalent to about 300 grams of TNT hidden in an electric scooter went off as the servicemen were walking to their official car in the early hours of the morning. Authorities have not yet clarified responsibility for the attack, the second in less than a week following the shooting death of the designer of the Kh-59 and Kh-69 cruise missiles, Mikhail Shatsky, in the Russian capital.