Diplomatic engagements at the highest level have changed the backdrop for discussing one of the world's most serious security challenges - North Korean nuclear and missile development, said South Korea's top diplomat.

Two leaders' summits between the Koreas and the historic summit between North Korean leader Kim Jong Un and United States President Donald Trump have led to "a very much changed context" to tackle the North Korean nu-clear issue, Dr Kang Kyung-wha told The Straits Times in an interview yesterday.