It's time for Western partners to take responsibility for ending the war unleashed by the Russian Federation in Ukraine, only a closed sky will stop the escalation, Mykhailo Podoliak, adviser to the President's Office head, said.

"The logic of this war is the build-up of missile and air strikes on civilian infrastructure, large cities and civilians. Only a 'closed sky' will sharply stop the escalation. It's time for Western partners to take responsibility for ending the war," he said on Twitter on Friday.