i am erin burnett. out front tonight, the defense department announcing 3,000 more u.s. troops are now heading to eastern europe, as there is growing intelligence that putin is ready to go to war now. >> it is an urgent message because we are in an urgent situation. we are in a window when an invasion could begin at any time. >> the national security adviser, jake sullivan, saying putin, who currently has ukraine surrounded on three sides with ground troops, may even give the go order before the olympics and in nine days. if that happens, the white house predicts it will be swift and deadly. >> if a russian attack on ukraine proceeds, it is likely to begin with aerial bombing and missile attacks that could obviously kill civilians without regard to their nationality. a subsequent ground invasion would involve the onslaught of a massive force. but i want to be equally clear that one of those forms is a rapid assault on the city of