Russia mounted an intense missile and drone barrage of the Ukrainian capital overnight, killing four people, Ukrainian officials said, as powerful explosions reverberated across the city. The attack followed a warning from Russian President Vladimir Putin,

Russian President Vladimir Putin told President Donald Trump in a phone call Wednesday that he was obligated to respond to Ukraine’s weekend drone attack, Trump said, setting up a potential escalation in the conflict just as the US president hopes to broker an end to the war.