The statement was made after a meeting with his US and Japanese counterparts, Jake Sullivan and Shigeru Kitamura.

The three also agreed that "efforts to resume North Korea-US negotiations at an early date must continue," he added.

Friday's meeting was the first of its kind since US President Joe Biden took office on January 20. Negotiations between the US and North Korea have been in a deadlock since former US President Donald Trump and North Korean leader Kim Jong Un met in February 2019.