Russian attacks on Ukraine’s energy infrastructure cut power to hundreds of thousands of homes in the Dnipropetrovsk and Kharkiv regions, authorities and an energy provider said on Sunday.

Ukraine is bracing for another harsh winter of war as Russia steps up daily aerial barrages, raining down drones and missiles on the power network.

In the central Dnipropetrovsk region, “more than 600,000 residents of the region have been left without power,” the DTEK power company said on Telegram after a “night attack has damaged important energy facilities.”

It said the company was working to restore electricity, but the task was “complicated by repeated attacks.”

In another strike, a Russian drone hit “a critical infrastructure facility” in the northeastern Kharkiv region, said Mykola Baksheyev, mayor of the city of Zlatopil, on social media.

“Nearly 250,000 customers in the Kharkiv region were left without power,” Baksheyev said.

Repair works were underway, but “the exact time for restoring power supply is still unknown,” he added.

The strikes came a day after Ukraine’s energy ministry said a massive attack on energy facilities had plunged residents in five regions into darkness and significantly hampered electricity transmission in Kyiv.

President Volodymyr Zelensky has accused Russia of intensifying strikes to put pressure on Kyiv at US-brokered trilateral talks in Abu Dhabi scheduled for Tuesday and Wednesday.

Russia has battered Ukraine’s energy grid and infrastructure throughout its four-and-a-half-year invasion, and Kyiv was now entering another wartime winter with temperatures already hovering around freezing.