Overnight and early morning Ukrainian drone strikes have killed at least four people in the annexed Crimean peninsula, local authorities said Thursday.

Sergei Aksyonov, the Russian-appointed governor of Crimea, said three people were killed in an attack on “non-residential targets” in the central city of Simferopol at around 1:40 a.m. Moscow time.

A fourth person was killed and three others wounded in an attack on a train heading from the town of Azovske to the eastern port of Kerch, Aksyonov wrote on Telegram later in the morning.

In the port city of Sevastopol, the Kremlin-installed Governor Mikhail Razvozhayev said air defense systems intercepted more than 52 Ukrainian drones, adding that no one was injured.

Razvozhayev said the “difficult night” prompted Crimea’s largest gas station network, TES, to again suspend the distribution of gasoline vouchers amid a fuel shortage in the region.