on this frozen landscape in eastern ukraine. with russian-backed rebels on one side and ukrainian troops on the other. this is the front line. the skarps from this conflict are everywhere across eastern ukraine. although there s supposed to be a peace agreement here, artillery shells are being swapped by both sides and every few minutes, we hear the sound of small arms fire. today, as many as 100,000 russian combat troops are thought to be massed on the border near here. the u.s. fearing they could be preparing for full-scale military assault into ukraine. the white house has been saying for days that russia is planning to invade.pthe kremlin denies te troop buildup is very, very real. so, we re being told that when the president speaks to vladimir putin tomorrow, his message is going to be tough, not finger wagging, but it s going to be crystal clear. don t go there. david? all right, ian pannell and our team from inside ukraine tonight. thank you.