conversation between vladamir putin and joe biden. the white house says it was a serious and substantive conversation. during the phone call, joe biden again warned of dire economic consequences if russia invades ukraine. vladamir putin fired back saying that would be a colossal mistake. jeremy diamond has the latest. reporter: for the second time in a matter of weeks, joe biden and russian president vladamir putin getting on the phone together for a one on one conversation, focused particularly on those rising tensions between russia and ukraine. the prospect, of course, of a war between those two countries looming over the 50-minute conversation between the two leaders that took place on thursday. joe biden phoning in from his wilmington, delaware home. an administration official telling us the tone of the conversation was substantive and serious. and the white house press secretary jen psaki making clear that joe biden urged russia to