our pentagon correspondent barbara starr. barbara, what has been the reaction on this latest stance in the ukraine? >> well, what you're hearing is what we've been hearing for several weeks, that russia has to de-escalate the position. the u.s. has the position that it's russian agents and provacateurs, that they have to stop that violence and they have to pull back on the 40,000 troops that u.s. says is on that ukraine-russia border. the russian foreign minister sergey lavrov said the big concern now is that all of this will add up to basically the provocation that the u.s. fears russia has been waiting for in