Ukraine used drones to strike Russian heavy bomber planes at air bases in Siberia and the far north at the weekend, and Russia also accused it of blowing up rail bridges in the south of the country, killing seven people.

Moscow said on Wednesday that military options were "on the table" for its response to Ukrainian attacks deep inside Russia and accused the West of being involved in them.

Ukraine's audacious targeting of major Russian airbases is "grounds for a nuclear attack," a prominent Kremlin propagandist and ally of Russia's President Vladimir Putin has said. Ukraine launched simultaneous attacks on multiple Russian airfields on Sunday in an operation dubbed "Spiderweb,