Russian President Vladimir Putin told US President Donald Trump in a phone call Wednesday that Moscow 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.

Ukraine’s bold attacks targeting key assets in Moscow’s war effort have struck a nerve with Russia – which launched another deadly missile and drone attack overnight. Bombs hit Ukraine’s capital Kyiv,

Trump said his latest call with Putin wouldn't lead to "immediate peace" as he relayed the Russian leader's plans to retaliate against Ukraine.