By Anastasiia Malenko

KYIV (Reuters) -Russia targeted Ukrainian energy facilities in a new wave of airstrikes, Ukrainian officials said on Thursday, despite a U.N. monitoring body saying attacks on the power grid probably violated humanitarian law.

Regional officials said civilian infrastructure had also been damaged, and the International Energy Agency warned of an electricity shortfall in Ukraine this winter.

Ukraine’s air force said it had shot down all 42 drones and one of four missiles launched by Russia in the latest attacks in more than 2-1/2 years of war since Russia’s full-scale invasion.

Three people were killed in shelling near Krasnopillia in the Sumy region on Wednesday evening and two were wounded in daytime shelling of the frontline region on Thursday that damaged a medical institution, local prosecutors said.

Ukraine’s energy ministry said power cuts had been introduced in 10 regions, and the IEA said in a report that Ukraine’s electricity supply shortfall in the critical winter months could reach about a third of expected peak demand.

In a sign of its concern, the European Union said a fuel power plant was being dismantled in Lithuania to be rebuilt in Ukraine, and that electricity exports would also be increased.

The U.N. Human Rights Monitoring Mission in Ukraine said Russia’s strikes on the energy grid posed risks to the water supply, sewage and sanitation, provision of heating and hot water, public health, education and the wider economy.

“There are reasonable grounds to believe that multiple aspects of the military campaign to damage or destroy Ukraine’s civilian electricity and heat-producing and transmission infrastructure have violated foundational principles of international humanitarian law,” it said in a report.

Kyiv says the targeting of its energy system is a war crime, and the International Criminal Court has issued arrest warrants for four Russian officials and military officers for the bombing of civilian power infrastructure.

Moscow says power infrastructure is a legitimate military target and has dismissed the charges against its officials as irrelevant.

REPEATED ATTACKS

Moscow has repeatedly attacked the Sumy region since Ukraine began an incursion into Russia’s Kursk region last month in which Kyiv says it seized over 100 settlements.

Russia has taken back two more villages in Kursk, a senior commander said on Thursday, adding that Russian forces were also advancing in eastern Ukraine.

Ukrainian air defences went into operation in nine Ukrainian regions overnight, the air force said, and the governor of the central Dnipropetrovsk region said a missile had been shot down over his region.

Six people were wounded in Kupiansk in the northeastern region of Kharkiv, and a school and a kindergarten were among buildings damaged, the regional governor said.

An educational institution was also reported damaged in the Cherkasy region although Russia has denied targeting civilians.

(Additonal reporting by Olena Harmash, Editing by Timothy Heritage)