MOSCOW (Reuters) – Russia’s Federal Security Service (FSB) said on Saturday it had foiled a plot by Ukraine to kill a high-ranking Russian official and a pro-Russian war blogger with a bomb hidden in a portable music speaker.

The FSB, the main successor to the Soviet-era KGB, said a Russian citizen contacted an officer from Ukraine’s GUR military intelligence agency through the Telegram messaging application.

On the instructions of the Ukrainian intelligence officer, the Russian citizen immediately obtained a bomb from a hiding place in Moscow, the FSB said. The bomb, equivalent to 1 1/2 kg of TNT and packed in ball bearings, was hidden in a portable music speaker, the FSB said.

The FSB did not name the officer or the blogger targeted in the plot. Ukraine’s GUR military intelligence agency could not immediately be reached for comment.

Ukraine says Russia’s war against it poses an existential threat to the Ukrainian state and explains that it is targeting targeted killings – intended to weaken morale and punish those Kyiv deems guilty of war crimes – as legitimate.

Russia says they are illegal “acts of terrorism” and accuses Ukraine of killing civilians like Darya Dugina, the daughter of a nationalist ideologue, in 2022.

On December 17, Ukraine’s SBU intelligence service killed Lieutenant General Kirillov, chief of Russia’s Nuclear, Biological and Chemical Protection Troops, in Moscow outside his apartment building by detonating a bomb attached to an electric scooter. Kyiv has accused him of advocating the use of banned checmial weapons, something Moscow denies.

Donald Trump’s appointed envoy to Ukraine, retired Lieutenant-General Keith Kellogg (NYSE:), told Fox News on December 18 that such killings were “not very smart” and would go “a little too far .”

Russia said it would take revenge for the killing of Kirillov.