dte to ea wih ukraieve a russiat today with american and allied officials at nato headquarters in brussels. after four hours of talks, chief u.s. negotiator wendy sherman said russian military movements make it all the harder to defuse the crisis. >> is this about invasion? is this about intimidatio? this about trying to be subversive? i don't know. but it is not conducive to getting to diplomatic solutions. >> reporter: russia's putin is trying to roll back the nato alliance, which has expanded dramatically in the last two decades. he is demanding ukraine never be allowed to join and that military deployments be halted just last month, american. f-15s were operating out of one airfield in romania, while u.s. helicopters flew into another. ded nce putin annexed