Vladimir Putin

MOSCOW, RUSSIA - JUNE 25: Russian President Vladimir Putin walks by the grave of Soviet leader Josef Stalin, while visiting the Russian books festival in Red Square, on June 25, 2015 in Moscow, Russia. Russian President Vladimir Putin is not done in eastern Ukraine, NATO's top commander said on Thursday, cautioning that Russia has been building up supplies on its border with Ukraine and keeping its military options open. U.S. General Philip Breedlove, NATO's supreme allied commander, said the border between Ukraine and Russia was "wide open," allowing free movement of equipment and supplies. (Photo by Sasha Mordovets/Getty Images)