Russian strikes overnight left over 100,000 households without power in northern Ukraine and cut off the water supply to a regional capital, Ukrainian authorities reported Saturday, while civilian casualties rose sharply in the country's embattled east.

The northern Sumy region, which borders Russia, was plunged into dark after Russian strikes late Friday damaged energy infrastructure, the Ukrainian Energy Ministry said. Hours later, the Ukrainian public broadcaster reported that Russian drones hit the provincial capital, also called Sumy, cutting off water by hitting power lines that feed its system of pumps.

Russian state agency RIA cited a local pro-Kremlin “underground” leader as saying that Moscow's forces overnight hit a plant producing rocket ammunition in the city, which had a pre-war population of over 256,000. The report didn't specify what weapon was used, and the claim could not be independently verified. Explosions rocked the city during an air raid warning early Saturday, according to Ukrainian media reports.

In the Donetsk region in the east, Russian shelling on Friday and overnight killed 11 civilians and wounded 43, local Gov. Vadym Filashkin reported on Saturday. Five people died in the town of Selydove southeast of Pokrovsk, the eastern city that has emerged as a front-line hotspot. The Ukrainian General Staff on Saturday morning said that Ukrainian and Russian forces clashed 45 times near Pokrovsk over the previous day.

According to Filashkin, three more people died in Chasiv Yar, the strategically located town in Donetsk that has been reduced to rubble under a montshlong Russian assault.

A Ukrainian military spokesperson on Thursday told the AP that Ukrainian forces had retreated from a neighbourhood on the outskirts of Chasiv Yar. The town's elevated location gives it strategic importance, and military analysts say its fall would put nearby cities in jeopardy. It could also compromise critical Ukrainian supply routes and bring Russia closer to its stated aim of seizing the entire Donetsk region.

According to the Ukrainian General Staff, Russian forces on Friday and overnight launched six rocket strikes and 55 airstrikes across Ukraine, and used more than 70 “glide bombs” — retrofitted Soviet-era weapons that have wrought devastation in the country in recent weeks.

In Russia, two civilians were wounded after Ukrainian forces overnight shelled a border town in the southern Belgorod region, its Gov. Vyacheslav Gladkov reported.

The Russian Defense Ministry said its troops overnight shot down a total of eight drones over the Kursk and Belgorod regions in the south.

In Krasnodar province next to Russia-annexed Crimea, local authorities reported on damage caused during the night by falling drone debris. Debris sparked a fire at an oil depot, set fuel tanks ablaze in a separate location and damaged a cellphone tower, the reports said. There were no immediate reports of casualties.