Russia launched an overnight drone attack across Ukraine on Saturday, hitting an energy facility in the Sumy region in the northeast of the country, officials said.

Ukrainian mobile drone hunter groups and air defense units shot down 24 of the 27 Russian drones fired on 12 regions, the air force said.

National grid operator Ukrenergo said the energy facility in the Sumy region was damaged, forcing emergency electricity shut-offs for industrial consumers in the city of Sumy. Repair teams were working to restore supplies, it said.

There were no immediate reports of casualties or other damage details from the regions.

Since March, Russian forces have intensified their bombardments of the Ukrainian power sector, knocking out the bulk of the thermal and hydropower generation and forcing long blackouts across the country.

Ukrenergo planned scheduled cut-offs of electricity throughout the day across the country as domestic generation and electricity imports could not cover the deficit.

Ukraine’s energy system was already hobbled in the first year after Russia’s invasion in February 2022. The power system lost about half of its available generation capacity due to the Russian missile and drone attacks in the past four months.