The warning comes after independent UN experts said in August that North Korea generated an estimated $2 billion for its weapons of mass destruction programmes using cyberattacks to steal from banks and cryptocurrency exchanges.
UN sanctions experts are warning people not to attend a cryptocurrency conference in North Korea in February, flagging it as a likely sanctions violation, according to a confidential report due to be submitted to the UN Security Council later this month.
The warning comes after the independent UN experts told the council in August that North Korea generated an estimated $2 billion for its weapons of mass destruction programmes using "widespread and increasingly sophisticated" cyberattacks to steal from banks and cryptocurrency exchanges.
North Korea has been under UN sanctions since 2006 over its nuclear and ballistic missile programmes. The 15-member Security Council has unanimously strengthened those measures over the years, prompting Pyongyang to look for alternative ways to make money.
In April last year, North Korea held its first blockchain and cryptocurrency conference and an organiser said more than 80 organisations took part. An American who attended has been charged with violating US sanctions.
The next conference is due to be held from February 22 to 29, according to its website.
An excerpt from the upcoming annual report by the UN sanctions experts, seen by Reuters, warns that presentations at the conference "have included explicit discussions of cryptocurrency for sanctions evasion and money laundering."
It then spells out that UN sanctions require countries to prevent the provision of "financial transactions, technical training, advice, services or assistance" if they believe it could be contributing to North Korea's nuclear or ballistic missile programs or to the evasion of sanctions.
The full report is due to be submitted to the UN Security Council North Korea sanctions committee later this month.
North Korea's mission to the United Nations did not immediately respond to a request for comment.
No evidence of entry
A British government spokesman and a Security Council diplomat from another country, speaking on condition of anonymity, both said North Korea's cyber programme was used to collect information, evade sanctions and generate revenue.
"Supporting the DPRK's use of cryptocurrency and blockchain technology, risks violating the Security Council's resolutions because it would unavoidably increase the DPRK's ability to subvert sanctions and generate revenue for its weapons programs," the British spokesman said, citing North Korea's official name, the Democratic People's Republic of Korea (DPRK).
US formally charged American digital currency expert Virgil Griffith last week after he attended the North Korean cryptocurrency conference last year. Prosecutors accuse him of providing services to North Korea without US approval and evading US laws.
When Griffith, who has a doctorate from the California Institute of Technology, was arrested in November, prosecutors said he and other conference attendees had discussed how cryptocurrency technology could be used by Pyongyang to launder money and evade sanctions.
"Although the press was not allowed to attend the conference and its proceedings were not published openly, the recent indictment of an American for sanctions violations sheds light on the intended purpose of the conference," the UN sanctions experts wrote in the excerpt from the upcoming report.
US prosecutors said Griffith had been encouraging other US citizens to attend next month's conference in North Korea.
The conference website specifically notes that Americans are welcome to apply to attend and that their passports would not be stamped "so there will be no evidence of your entry to the country".
Cryptocurrencies, like bitcoin and ether, are created through a computer process called mining, which requires powerful hardware. Once generated, they can be exchanged on anonymous online platforms for fiat currencies such as the US dollar, which in turn can help illicit activities like evading sanctions or laundering money.
Blockchain technology is a digital ledger that forms the backbone of many cryptocurrencies such as bitcoin.