North Korea has accused the UN and the US of "double dealing" for condemning Pyongyang's Intercontinental Ballistic Missile (ICBM) tests, a media report said on Sunday.

Ambassador Kim In Ryong, deputy permanent representative of North Korea, on Friday read out a letter here that threatened to ignore UN Security Council (UNSC) resolutions for discrimination and registered complaints against the world organisation and the US, Xinhua news agency reported.

"The sophism of the US claiming that it may carry out missile launches but not the DPRK and that its launches are a 'contribution' to peace and security while the one by DPRK is 'provocative' and strains tensions, is really the height of double-dealing standards," he said.

"The UNSC has kept mum about the US test-fire of an ICBM which flew more than 6,000 km across the ocean, even while crying out for 'denunciation' and 'sanctions' for ballistic rocket test-fires the DPRK carried out."

North Korea tested a Hwangsong-12 ICBM on May 14 which the council criticized, while the US tested ICBMs on April 26 and May 3 without criticism, the Pyongyang envoy said.

"If the UNSC does not call the US to account for its aggressive and provocative large-scale joint military exercises and ICBM launches, the DPRK will never recognise any UNSC 'resolution' taken over the DPRK's ballistic rocket launches but continue to disclose the absurdity of the UN 'sanction resolutions'," Kim said.

North Korea has ignored several resolutions against ICBM and nuclear weapons testing.

Kim said the UN has ignored requests for an "international forum of legal experts to clarify the legal basis of the 'sanction resolutions'."

North Korea's nuclear capability for self defence and deterrence is aimed at the US trying to antagonize, isolate and stifle the country, he said.

But, Kim said that if the Trump administration "truly wants to adopt a new policy towards the DPRK, drawing a lesson from the preceding administration's failure, it should replace the Armistice Agreement between the DPRK and US with a peace accord and the total removal of hostile relations".

Such a move would "help ensure lasting peace on the Korean peninsula and further global peace and security," he said.

A joint statement by US Secretary of State Rex Tillerson, Defence Secretary Jim Mattis and National Intelligence Director Dan Coats said the Us aimed to use economic sanctions and diplomatic measures to pressure Pyongyang to dismantle its nuclear and missile programmes.

The statement said the US remained "open to negotiations" toward the peaceful denuclearisation of the Korean peninsula while staying "prepared to defend ourselves and our allies".