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.

By Guy Faulconbridge and Rami Ayyub MOSCOW/WASHINGTON (Reuters) -Russian President Vladimir Putin told U.S. President Donald Trump on Wednesday that he would have to respond to Ukrainian drone attacks on Russia's nuclear-capable bomber fleet,

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,