sneak's leader says his country is close to conducting nuclear tests. several in 2016 were believed to have been successful. barbara starr joins us now. is there a reason to take this new threat more seriously? >> this appears to be every are on the take it seriously because north korea is on this march towards a nuclear weapons capability. and there are no signs they are giving it up. as you said, they have conducted up ground tests. they have been successful. they have conducted several missile test, some long range, some of them working better than others. but they are working on that program. and what u.s. officials are telling us is that every sign they see is that north korea is now putting everything it's got into this weapons development program. they are not pulling back. they are moving ahead on all fronts. and the key yes now is when can