North Korean leader Kim Jong Un broke his silence this week for the first since his historic Singapore Summit with President Trump last month; hailing his new relationship with the United States and saying he has the utmost "confidence" the two nations can work together.
Trump suggested on Monday that China, North Korea's neighbor and main trading partner, might be seeking to derail US efforts aimed at denuclearizing North Korea, but said he was confident that Kim Jong Un would uphold the pact the two agreed in Singapore.
The letter's date indicates it was written before Secretary of State Michael Pompeo's visit late last week to Pyongyang, where the USA and North Korea struggled to agree over plans to denuclearise the Korean peninsula.
In the letter dated July 6, Kim thanked Trump for his "energetic and extraordinary efforts" to improve the once hostile relations between the two countries.
The repatriation of the remains of USA soldiers from North Korea has been a major issue between Washington and Pyongyang since the end of the Korean War, when thousands of Americans were left in Korea either missing in action or as prisoners of war.
In its report, the United States pointed the finger at China and Russian Federation for continuing to sell refined petroleum products to North Korea. They signed a joint statement reaffirming North Korea's commitment to giving up nuclear weapons.
Representatives of the US and North Korea were expected to have working-level talks at the inter-Korean border truce village of Panmunjom on Thursday to hash out the details of the repatriation, but the discussions did not occur.
But readers soon pointed out that the letter didn't actually mention any action that had been taken, and only made vague promises about 'the future progress of taking practical actions'.
This would signal a shift in tone from Pyongyang's previous unwillingness to open up dialogue with Tokyo, which has been somewhat sidelined amid the flurry of diplomacy over North Korea's nuclear program, resulting in a recent thaw in relations between the North and the United States. South Korea's Yonhap news agency, citing unnamed sources, said the North requested talks at a higher level.
The US later said that North Korea had offered to meet on 15 July.
Trump is making the letter public at a time when his North Korea claims are coming under question.
There is speculation that North Korea may also want payment for the return of the remains, our correspondent adds. The expected North Korean officials never arrived, according to the official who requested anonymity as he was not permitted to talk publicly about the event.
The UN Security Council has unanimously toughened sanctions on North Korea since 2006 in a bid to choke off funding for Pyongyang's nuclear and ballistic missile programmes, banning exports including coal, iron, lead, textiles and seafood, and capping imports of crude oil and refined petroleum products.
"Most important, instead of any hint of criticism of President Trump, the statement ends on a positive note: 'We still cherish our good faith in President Trump, ' underlining that the problem is not the President but rather 'headwind against the wills of the two top leaders...,'" he highlighted.