North Korea said on Sunday there has been no progress in the North Korea-United States relations, and hostilities that could lead to an exchange of fire have continued, according to North Korea's state news agency KCNA.

In a statement under the name of North Korea senior official Kim Yong-chol, KCNA said that it would be mistaken for the United States to ignore a year-end deadline on US President Donald Trump's and North Korean leader Kim Jong-un's "close personal relations."

Kim Jong-un has set an end-of-the-year deadline for denuclearisation talks with Washington. 

Kim Yong-chol was the nuclear talks envoy to the United States for the discussions between the two countries before the second summit between Trump and Kim Jong-un in Vietnam in February ended in failure.

Kim Yong-chol said the United States has been pressuring North Korea in a "more crafty and vicious way" instead of heeding North Korea's call for Washington to adopt a new approach, adding that the United States has been persistently pushing other countries to impose UN sanctions on North Korea.

The statement quoted Kim Yong-chol as saying he hopes that US-North Korean relations do not underscore that "there are permanent foes but no permanent friends."

The statement comes just days after North Korea asked South Korea to discuss removal of its facilities from the North's resort of Mount Kumgang, a key symbol of cooperation that Pyongyang recently criticised as "shabby" and "capitalist."

North Korea on Friday sent notices to the South's Unification Ministry, which handles issues between the two sides, and Hyundai Group, whose affiliate Hyundai Asan Corpbuilt the resort facilities, asking for their demolition and seeking discussion through the exchange of documents, the ministry said. (Reuters)