US suggests N Korea may be able launch nuclear weapon
12 April 2013 Last updated at 07:14 BST
The American Secretary of State is in the South Korean capital Seoul, for talks about the nuclear crisis.
John Kerry's visit comes as the Pentagon plays down an intelligence report suggesting Pyongyang is able to mount nuclear warheads on missiles.
President Obama has warned North Korea to end what he called its "belligerent approach".
John Sudworth reports.