aircraft carrier in a single strike. president trump talking to leaders of china and japan last night. paula hancocks joins us from seoul, south korea. let's start with the u.s. citizen detained. what are we learning? >> reporter: well, dave, we know his name is tony kim. we know that he was a professor, we believe, teaching at the pyongyang university of science and technology. we had a statement from that school. they said he was detained as he was trying to get on a plane to leave pyongyang. they don't believe his teaching had any part of why he was detained. they don't, however, give us any indication as to why he was taken, what the allegations against him, what's he accused of. we don't know because the north korean regime up to this point has not officially said anything. the state department is looking into this closely, working with the swedish embassy. washington doesn't have diplomatic ties with pyongyang so they have to work with sweden to get any information and any access and they also say he was