Ukraine says it has obtained an intercepted Russian plan for a winter campaign against its energy grid. Here is what is known so far.

Energy Minister Denys Shmyhal showed the document to European partners in Paris about two weeks ago, and the New York Times obtained a copy. It describes three stages of strikes on substations, hydro plants and switchyards.

The targets include switchyards less than a mile from three nuclear plants. The plan reportedly aims to knock out about 15 gigawatts of capacity and cut electricity and heating by up to 90 percent in Kyiv, Kharkiv and Odesa.

Ukraine says up to 1,000 missiles, drones and guided bombs could be used. Russia has already stepped up strikes on energy sites. Western officials say the plan may be bluster, but Kyiv is taking it seriously.

Analysts caution that the document may overstate Russian capabilities. Ukraine’s air defences have improved with Western support, and repairs have made the grid more resilient. Still, last winter’s strikes caused long blackouts. Ukraine is asking allies for more air-defence systems and backup power equipment before winter.