US President Donald Trump praised North Korean leader Kim Jong Un on twitter today. (File)

US President Donald Trump praised North Korean leader Kim Jong Un on Thursday for reportedly expressing faith in him.

"Kim Jong Un of North Korea proclaims 'unwavering faith in President Trump.' Thank you to Chairman Kim. We will get it done together!," Trump wrote on Twitter.

Kim restated his commitment to denuclearizing the Korean peninsula Thursday.

South Korean National Security Advisor Chung Eui-yong delivered a letter Wednesday to Kim from South Korea's President Moon Jae-in.

Trump and Kim pledged to denuclearise the Korean peninsula at the Singapore summit in June but no details were agreed. And Washington and Pyongyang have sparred since on what that means and how it will be achieved.

Kim emphasised that his "trust in Trump remains unchanged" despite the difficulties, Chung said, and expressed his intention to work closely with the United States to achieve denuclearisation "in the first official term of President Trump."