korean state media calling for an end to the confrontation between north and south. this follows news a fourth american detains by pyongyang. we have cnn's ivan watson from seoul. ivan, what do we know about the fourth american detained in pyongyang? >> reporter: he is an academic. u.s. citizen teaching at pyongyang university of science and technology. he is now the second american professor in just over two weeks who had been teaching there detained by the north koreans on suspicious of crimes against hostile against the north korean regime. the situation very serious for the american citizens because of course we have a period of confrontation with pyongyang and washington over the north korean nuclear program and no formal diplomatic relations with the governments. the u.s. has to work through