Ukrainian drones have struck a large military depot in a town deep inside Russia overnight, causing a huge blaze and prompting the evacuation of residents.

Ukraine struck the Moscow region on Tuesday in its biggest drone attack so far on the Russian capital, killing at least one woman, wrecking dozens of homes and forcing around 50 flights to be diverted from airports around Moscow.

The strike came as a senior US diplomat said that Ukrainian President Volodymyr Zelensky's recently announced — but still confidential — plan for winning the war "can work" and help end the conflict that is now in its third year.