Russian shelling damaged a thermal power plant in southern Ukraine late on Wednesday, Ukraine's national grid operator said.

State-run Ukrenergo gave no other details of the location of the plant or the extent of the damage.

"Yesterday evening a thermal power plant in the southern region was damaged as a result of massive enemy shelling," Ukrenergo said in the statement released on Thursday.

In an emailed comment to Reuters, Ukrenergo said it was not able to provide other details under current legislation during wartime.

Russia unleashed waves of air attacks on Ukrainian power plants and transformers last winter that left millions of people without electricity at times.

It struck energy facilities across Ukraine last week, disrupting power supply in five region, and attacked unspecified infrastructure early on Thursday.

Ukraine has carried out extensive repairs of its power infrastructure but officials have warned of new attacks this winter and called on allies to bolster Kyiv's air defences.

Ukrainian President Volodymyr Zelenskiy discussed the possibly of NATO members supplying additional air defence systems during talks with the military alliance's secretary general, Jens Stoltenberg, in Kyiv on Thursday. (Reporting by Anna Pruchnicka, Editing by Timothy Heritage)