Ukraine has "changed the narrative around the war" with their attack on the Kursk region, the president of the Council on Foreign Relations has told Sky News.
Michael Froman said Ukrainian troops had shown they could take the war to Russia's territory and not just be on the defensive.
"They have also changed the narrative around Vladimir Putin and whether he was really in control of his own territory and capable of protecting Russians," he said.
"Russians have been quite surprised they've had to be evacuated from the Kursk region."
He noted though that Ukraine had hoped the operation in Kursk would pull some of the Russian troops away from the eastern Donetsk region but instead the "Russians had doubled down there".
"That poses a significant challenge to Ukraine about how long they can hold Kursk," he added.
