North Korea And United States Trade Nuclear Blows

North Korea is "alarmed" at the pressure mounted by the U.S. over the implementation of the nuclear disarmament deal.

North Korea and the United States have traded blows over implementing a disarmament deal adopted at a landmark summit in June.

Washington is calling for maintaining sanctions pressure against the North which in turn says it is alarmed at US intentions.

The discord is the latest reminder of the difficulties that have impaired efforts to negotiate an end to North Korea's nuclear and missile programs, despite the mid-year commitment made in Singapore by both nations.

"The DPRK stands firm in its determination and commitment for implementing the DPRK-US Joint Statement in a responsible and good-faith manner," North Korea's Foreign Minister Ri Yong Ho told a regional forum in Singapore on Saturday.

DPRK refers to his country's official name, the Democratic People's Republic of Korea.

"What is alarming however is the insistent moves manifested within the US to go back to the old, far from its leader's intention," Ri said.

Ri made the statement after US Secretary of State Mike Pompeo had left the conference for Indonesia, a State Department spokeswoman said.

At the summit on June 12, US President Donald Trump and North Korean leader Kim Jong Un, who is seeking relief from tough sanctions, committed to work towards denuclearisation but Pyongyang has offered no details on how.

Trump and Kim shake hands after signing a document following their summit (REUTERS/Jonathan Ernst)

Pompeo pressed Southeast Asian nations in Singapore this week to maintain sanctions on North Korea but said he was optimistic the deal to end the North's nuclear program would work out.

"We have initiated goodwill measures of, inter alia, a moratorium on nuclear tests and rocket launch tests and dismantling of nuclear test ground," Ri said in a statement to the Association of Southeast Asian Nations forum.

"However the United States, instead of responding to these measures, is raising its voice louder for maintaining the sanctions against the DPRK and showing the attitude to retreat even from declaring the end of the war."

Pompeo suggested on Friday continued work on weapons programs by North Korea was inconsistent with Kim's commitment to denuclearise.

On Saturday, he stressed diplomatic and economic sanctions on the North must be maintained in order to achieve a complete end to the nuclear program, carried out in defiance of UN Security resolutions.

He also said Washington took very seriously any relaxation of UN sanctions, calling out Russia for possibly violating a UN resolution by issuing work visas to North Korean workers.