Ukraine's security service on Tuesday claimed responsibility for killing the head of Russia's chemical, radiological and biological weapons unit, Lt. Gen. Igor Kirillov. The Security Service of Ukraine (SBU) was behind the detonation of an explosive device planted in a scooter next to the entrance of an apartment building in Moscow, according to a Ukrainian source briefed on the matter within the who asked for anonymity because they are not authorized to speak publicly about sensitive...