of deterring russia is working? >> we have a long way to go. i think we have to continue to increase our ability to move quickly there. because a true deterrent, one where people are worried if they conduct operations there will be some level of response. we have to improve what that level of response may look like. so we can deter. >> reporter: with russia undeterred in ukraine, u.s. and nato leaders are concerned moscow may attempt to destabilize nato allies neighboring russia. lithuania, latvia, and estonia. >> how concerned are you that russia will try the same strategy in nato allies bordering russia? >> russia is assessing the reaction of nato to any of their actions. what i were radioaboorry about and violate article 5 of the nato agreement. i asked the general if they have the deterrent capability to deter russia. he said in his word, it has some, not a ringing endorsement