North Korean leader Kim Jong Un has expressed eagerness for a second summit with US President Donald Trump planned for late next month.

The state-run Korean Central News Agency reported on Thursday that Kim's close aide Kim Yong Chol briefed the leader on Wednesday about his trip last week to the US, where he met Trump and other administration officials.

KCNA said Kim expressed satisfaction at receiving a letter from Trump, and welcomed the US president's strong will and ability to make decisions to solve problems.

Kim reportedly said he will believe in Trump's positive way of thinking, wait with patience and in good faith, and advance step by step with the US toward the goal to be reached by the two countries.

However, diplomatic observers say the two sides remain at odds over denuclearization. North Korea is demanding that economic sanctions be eased, claiming it has taken steps such as shutting down a nuclear test site. The US insists on more concrete steps by the North.

NHK