like a phone conversation between vladimir putin and u.s. president joe biden. that happened on saturday. however, the russians are saying that they believe that there are still unanswered questions to which they would like to have further conversations with the white house. all this comes as the u.s. says the russians are continuing to amass forces near the borders with ukraine. several thousand more troops arriving there this past week alone. reporter: i m sam kiley in kharkiv. it is only 50 miles to the north around the city of bell grad where there is russian fire power. hundreds of tanks, thousands of infantry and all the pan my of modern weaponry amidst warnings from the united states that an invasion is imminent.