US President Donald Trump said he is “not happy” after Russia launched its deadliest wave of attacks on Kyiv in nine months, telling President Vladimir Putin to “STOP!” as he attempts to push Ukraine to agree on a contentious ceasefire proposal.

Despite negotiations to end the war in Ukraine hitting a wall and a deadly Russian strike on the country's capital city early Thursday, President Donald Trump remained insistent that talks had made "a lot of progress.

Vladimir, STOP!” the U.S. president wrote in a social-media post addressing the Russian leader, after the largest attack on Ukraine’s capital this year.