MOSCOW - Ukraine struck a heat and power station in the Moscow region on Sunday with drones, triggering a major fire and cutting off heating for thousands in one of Kyiv's biggest attacks to date on a power station deep inside Russia.

In the fourth year of the deadliest European conflict since World War Two, Russia has been pummelling Ukraine's electricity and heat infrastructure while Kyiv has up until now mostly focused on trying to knock out Russia's oil refineries, crude terminals and pipelines.