BRUSSELS, April 29 - NATO has seen no sign that tens of thousands of Russian troops are withdrawing from close to the Ukraine border, a NATO official said on Tuesday, despite a Russian statement that the troops had returned to their permanent positions.

Russian Defense Minister Sergei Shoigu told U.S. Defense Secretary Chuck Hagel in a phone call on Monday that Russian forces, which started drills near the border last week, had returned to their permanent positions, according to the Russian government.