reporter: the meetings led by mattis,ings dunford, secretary of state rex tillerson and dan coats. senators from both parties stressed the seriousness of the threat but said no new information was given, raising questions about whether a trip to the white house was necessary or just for show. reporter: you were inside. what was the revelation? no rev layings. i think the white house wanted to convey to the congress that they re serious about north korea. they clearly are, putting a lot of their cards on the table with china to try to get them to change their policy. i didn t hear anything that s different from public knowledge. reporter: he says he s taking the north korean leader at his own word, that he is developing a weapon capable of hitting the u.s. we re looking at it as if kim