NEW York:- A UN report says North Koreainfo-icon continues its weaponsinfo-icon programs despite its leader's promise to denuclearize.

The six-month confidential report from independent experts monitoring Pyongyang's nuclear and missileinfo-icon activities, cited by Reuters, said the North is still developing its weapons programs.

Pyongyang has "continued to defy Security Council resolutions through a massive increase in illicit ship-to-ship transfers of petroleum products, as well as through transfers of coal at sea during 2018," the report said.

This is not the first time that reports are suggesting Pyongyang is pressing ahead with its nuclear and missile activities since USinfo-icon President Donald Trumpinfo-icon met with North Korean leader Kim Jong-un in June.

The report came as US Secretary of State Mike Pompeo called for more diplomatic and economic pressures on North Korea over its nuclear weapons program.

"The work has begun. The process of achieving denuclearization of the (Korean) peninsula is one that I think we have all known would take some time," Pompeo said on the sidelines of the ASEAN security forum in Singaporeinfo-icon on Saturday.

The Wall Street Journal claims Russiainfo-icon allows entry of thousands of North Korean workers in violation of UN sanctions

"I'm optimistic that we will get this done in the timeline and the worldinfo-icon will celebrate what the UN Security Council has demanded," he added.

He is on a visit to the South Asian country to attend meetings of the foreign ministers of the Association of Southeast Asian Nations (ASEAN) as well as Chinainfo-icon, Russia, Japaninfo-icon and South Koreainfo-icon.

North Korean Foreign Minister Ri Yong Ho is also attending the conferences.

Pompeo visited Pyongyang last month for inclusive talks aimed at agreeing a denuclearization roadmap, but North Korea accused his delegation of making "gangster-like" demands.

US Secretary of State Mike Pompeo disembarks from a plane upon his arrival at the Royal Malaysian Air Force base in Subang, outside Kuala Lumpur, on August 2, 2018. (AFP)

A senior US official said on Monday spy satellites had detected renewed activity at the North Korean factory that produced the country's first intercontinental ballistic missiles capable of reaching the United Statesinfo-icon.

The Washington Post also claimed that North Korea appeared to be building one or two new liquid-fueled intercontinental ballistic missiles at the researchinfo-icon facility. 

Kim and Trump met in Singapore in June, and announced a broad statement on working towards denuclearization.

Trump declared after the summit that North Korea was "no longer a Nuclear Threat" to the US, but Washington maintains sanctions on Pyongyang.