The attack on Friday, which killed at least four people nationwide, came two days after Russia vowed retaliation for an audacious drone assault on its strategic bomber bases.

Days after Ukraine hit more than a third of multiple nuclear-capable bombers in Russia, Moscow launched a scathing attack on almost all of Ukraine, firing over 400 drones and 40 missiles. At least nine regions were affected with the missiles and drone attacks. They include Kyiv, Lviv, and Sumy.