At least six people were killed in a wave of Ukrainian drone attacks targeting Russia’s Belgorod and Perm regions and annexed Crimea overnight, officials said Monday.

A man and woman were killed when a drone struck their car in the Belgorod region near the border with Ukraine, according to the local emergency headquarters.

On Monday morning, officials in Belgorod said a man was killed in a separate drone attack in the border town of Grayvoron.

In the Perm region, 1,300 kilometers (800 miles) east of Ukraine, one person was killed and four were injured after a drone hit an apartment building, Governor Dmitry Mahonin said.

Unverified reports said smoke was seen rising over an industrial area in Perm that houses at least two defense facilities, including a gunpowder plant and a rocket engine manufacturing facility.

Meanwhile, in annexed Crimea, a 15-year-old girl and a man were killed in an overnight attack in the port city of Sevastopol. Kremlin-installed authorities said shrapnel-laden drones damaged windows in eight apartment buildings and a kindergarten.

Russia’s Defense Ministry said it intercepted 306 Ukrainian drones across Russia and annexed Crimea between Sunday evening and Monday morning.