it was not a rudimentary bomb. a certain level of sophistication went into it. they want to make sure they find the bomb maker before reports start to good the public domain and before potentially another attack could happen. >> live for us in manchester. thank you for the reporting. also one hour from now president trump will arrive at nato headquarters. let's go to our white house correspondent. she's traveling with the president. you know, he has now reversed course on thinking nato is answer leet. but he hasn't come out fully supporting saying the u.s. will stand behind its article five obligation. do we expect to hear that today? >> that's a great question. we have heard that from a number of his senior advisors, that they do support article five. when one of these countries is attacked, all of them are attacked. it's only been turned at one point when the u.s. was attacked