United States President President Donald Trump has had a letter delivered to North Korea's Kim Jong-un at an Asian security forum in Signapore.
It comes as North Korea's foreign minister, Ri Yong Ho, hit out at the United States for certain "alarming" moves, including "raising its voice louder for maintaining the sanctions against" the North.
Those moves, Ri told fellow ministers, could make an agreement with the Trump administration, including the North's commitment to work toward complete denuclearisation of the Korean Peninsula, "face difficulties."
Despite this, US Secretary of State Mike Pompeo, who delivered the letter, tweeted the pair had "a quick, polite exchange," Mr Pompeo tweeted.
The Presidents letter is reportedly in response to Kim Jong-un's letter, which Mr Trump tweeted about earlier in the week, while he thanked the North Korean leader for returning the remains of Americans.
The contents of what was written inside either letter is unclear.
Mr Pompeo stressed the necessity to maintain full sanctions pressure on Pyongyang at the ASEAN meeting, while North Korea said the US was acting with "alarming impatience" regarding denuclearisation of the Korean Peninsula.
ASEAN foreign ministers, along with counterparts from China, Japan and South Korea, urged the U.S. and North Korea "as well as concerned parties to continue working towards the realisation of lasting peace and stability on a denuclearised Korean Peninsula," according to a draft communique they were to issue after their meetings Saturday, which was seen by The Associated Press.
In the communique, they would "note" - often a diplomatic subtlety for a reminder - the "stated commitment" of the Democratic People's Republic of Korea, the North's formal name, "to complete denuclearisation and its pledge to refrain from further nuclear and missile tests during this period."
A summary of a new report by experts monitoring U.N. sanctions against North Korea, which was sent to the Security Council Friday night and obtained by the AP at the United Nations, said North Korea has not stopped its nuclear and missiles programs and continues to defy the sanctions resolutions.
The North was also violating sanctions by transferring coal at sea and flouting an arms embargo and financial sanctions, the report said.
Ri said that while North Korea has "initiated goodwill measures" including a "moratorium on the nuclear test and rocket launch test and dismantling of nuclear test ground," the U.S. has gone "back to the old, far from its leader's intention."
"What is alarming, however, is the insistent moves manifested within the US to go back to the old, far from its leader's intention."
Although the historic June meeting between the two leaders was meant US officials were optimistic about the agreement, it appears Pyongyang has made little progress.
A United Nations report indicates North Korea was continuing with nuclear and missile programs and evading sanctions.
The United Nations said North Korea has not halted the missile program, but instead is selling weapons to the Middle East and Africa.
ASEAN hosted diplomats from 26 countries and the European Union, for talks on political and security issues effecting the Asia-Pacific region.