the worry is that they don't need ICBMs to get to us - they have a lot of submarines - they have Soviet era technology that includes probably nuclear tipped torpedoes that can be launched at quite a distance into, say, a harbour and they acquired some old Soviet subs for "scrapping" some time back that had launch tubes in the fin (conning tower) - bit of chopping and blending and they have something that can launch the short range missiles that they have already developed and proven..
BUT where did they get their nuclear material from in the first place?