Kremlin comments seem to confirm reports Putin told Trump Moscow was obliged to hit back

• Europe live – latest updates

Russia will respond to Ukraine’s daring drone operation “how and when” it sees fit, the Kremlin has warned, seeming to confirm reports Vladimir Putin had told Donald Trump that Moscow was obliged to retaliate.

Ukraine has been bracing for retaliation after its SBU security service carried out a surprise drone strike over the weekend, targeting four airbases and damaging up to 20 Russian warplanes deep inside the country, according to US officials.