a joint session of congress. it follows an agreement the white house signed yesterday to give south korea more insight into its nuclear planning. there s a committment to send nuclear armed submarines to south korea for the first time in decades. and in return, seoul has given an assurance it will not pursue a nuclear bomb of its own. mr yoon said the agreement would be critical for south korea as it stares down north korean aggression and chinese expansion in the indo pacific region. all it has to do is stop its nuclear programme and give a substantive denuclearisation process. i once again urge north korea to seize it provocations and take the right path. korea with the us will continue to work for north korea s denuclearisation. let s go live to capitol hill, and speak to the bbc s carl nasman. good to see you, important day and