Russian drone strikes near a nuclear power plant in western Ukraine this week have revived anxiety among Ukrainian officials and civilians over one of the most oppressive hardships of the war: a winter assault on their nation’s energy grid.

The strikes Wednesday, which landed near the Khmelnytsky nuclear facility, drew an angry response from President Volodymyr Zelenskyy of Ukraine, who said it was "highly likely” that the power plant was the target. They also prompted another warning from the head of the United Nations’ nuclear watchdog agency about the precarious nuclear safety situation in Ukraine.

Zelenskyy vowed Wednesday night that Ukraine would hit back at targets inside Russia if Moscow tried once again to plunge his nation into cold and darkness.