US ambassador says N Korea sanctions to stay until denuclearisation

The US ambassador to South Korea, Harry Harris, says sanctions will remain in place against North Korea until it gives up its nuclear weapons. 

This comes as Washington and Pyongyang prepare for their second summit slated for late this month.

Speaking at a security forum in Seoul, Harris also dangled the prospect of a "brighter, more secure and more prosperous future" for the country if it fulfills its denuclearisation commitment.

Bruce Harrison reports from Seoul: