Specks of black oil have rained down on part of Moscow after a refinery was hit during the largest Ukrainian attack since the start of the full-scale war, with close to 200 drones fired towards the Russian capital.
Columns of thick smoke billowed high into the sky and 17 people were wounded in the Moscow region, according to local governor Andrei Vorobyov.
Residents in the south-east of Moscow region told the BBC that a fine drizzle had left "unpleasant black spots" on their clothes.
Moscow authorities denied that any "oil rain" had been falling.
However, the city's official Telegram channel warned residents of the affected district to keep their windows closed and said families with children, elderly people and asthmatics should urgently leave the area.