US President Donald Trump on Thursday tweeted a letter to him from North Korean leader Kim Jong Un heralding "epochal progress" in U.S.-North Korea relations, despite signs that path-finding diplomacy between the adversaries is running into problems.
Trump described the letter as a "very nice note" and said, "Great progress being made!"
The letter is dated July 6. That's when Secretary of State Mike Pompeo visited Pyongyang and seemingly made little progress in fleshing out details of North Korea's commitment for "complete denuclearisation."
Kim made that commitment when he met Trump in Singapore last month. Kim also agreed then to repatriate remains of U.S. troops who died during the Korean War six decades ago.
A planned meeting Thursday between North Korean and US officials in the Demilitarized Zone between the two Koreas to discuss the return of the remains was postponed.
State Department spokeswoman Heather Nauert said North Korea called at midday Thursday and offered to meet on Sunday instead, reports abc News.
"We will be ready," she told reporters aboard Pompeo's plane, as the top U.S. diplomat flew home to Washington after attending a NATO summit.
It wasn't immediately clear what prompted the postponement.
South Korea's Yonhap news agency, citing unnamed sources, said the North requested talks at a higher level. The talks Sunday are expected to involve officials from the Pentagon and the U.N. Command, which commanded U.S.-led allied forces during the war and is involved in maintaining the armistice that ended the fighting in 1953.
Pompeo told reporters after his visit to North Korea last week that the meeting in the truce village Panmunjom was set for Thursday but "could move by one day or two."