will be severe consequences. reporter: abc news tonight given exclusive access to ukrainian forces training with u.s.-supplied javelin anti-tank missiles. this is part of what vladimir putin means by a red line. what he sees as america s, nato s growing involvement in ukraine. tensions still high, as we saw on the front lines, where ukrainian forces are fighting with russian-backed rebels. you can hear the sound of rapid automatic gunfire there. we were so close to the front, you could only whisper. the russian-backed accept are cysts literally about 50 yards, maybe less, just on the other side. there and beyond those lines, at the border, as many as 100,000 russian troops are now massed. by friday, biden hopes to announce a higher level meeting with some nato allies and russia to discuss the kremlin s concerns. perhaps offering a way out of this crisis. david? all right, ian pannell again