Ukrainian drone attacks set fire to an oil depot in southwestern Russia and disrupted air traffic in Moscow this morning.
Russia said two drones were shot down near the capital and it thwarted a separate coordinated attack on Crimea.
At least 30 flights were delayed and six cancelled at Moscow's major airports, Russian state news agencies said.
There were no casualties in the depot fire in the Oryol region, said governor Andrei Klychkov, but he did not specify whether the depot was hit by debris or targeted by the drone.
More drones were downed in the Voronezh region and on the grounds of a logistics centre in the Tula region, authorities said .
