Russia unleashed 35 self-detonating drones on Ukraine in the early hours of Monday morning as many people slept, damaging critical infrastructure in and around the capital, Kyiv.
Governor Oleksiy Kubela said the assault was "fairly serious," after three areas in the region were left without power supply.
The assault marks Moscow's third air attack on the city in six days.
Meanwhile, the Russian ruble fell to a more than six-month low against the dollar. As of around noon ET Monday, it was trading at 68.08 against the dollar.
The fall marks the ruble's lowest level since mid-May.