Ukraine’s electricity grid chief warned of hours-long power outages on Friday as Russia zeroed in on Ukraine’s energy infrastructure with heavy artillery and missile attacks that have interrupted supplies to as much as 40 percent of the country’s people at the onset of winter.

​Ukraine’s electricity grid chief warned of hours-long power outages on Friday as Russia zeroed in on Ukraine’s energy infrastructure with heavy artillery and missile attacks that have interrupted supplies to as much as 40 percent of the country’s people at the onset of winter.