"The winter will be the hardest of the previous three years," Oleksii Brekht, acting chairman of the board of NPC Ukrenergo, was cited as saying by state-owned broadcaster Suspilne.

He added that power consumption restrictions of up to eight hours may be necessary this winter on the coldest days.

“Currently, the enemy has focused its attention on border regions where active combat is ongoing. This affects six regions, where the focus has shifted from our generation facilities to the distribution system,” Brekht added.

He said protective measures are being organized for these facilities.

NPC Ukrenergo has stockpiled three times the usual amount of repair equipment to help ensure a stable heating season, Ukrainian national news agency Ukrinform reported.

Ukraine-Russia negotiations?

Ukraine and Russia are in the early stages of negotiations about potentially halting airstrikes on each other's energy facilities, the Financial Times reported, citing unnamed people familiar with the matter.

The FT, citing sources it said included senior Ukrainian officials, reported that Kyiv was seeking to resume talks that had come close to an agreement in August and were mediated by Qatar.