The group, known as Lazarus, was behind the 2017 WannaCry Ransomeware attack, which affected 200,000 computers worldwide, including the National Health Service.

North Korean hackers who previously attacked the NHS, among others, are believed to be behind the world’s largest cryptocurrency heist, worth over £450m.

The US Treasury Department linked the theft to a digital currency address used by a group dubbed Lazarus.

Hackers have stolen hundreds of millions of pounds worth of cryptocurrency from the online game Axie Infinity.

Blockchain analytics firms said the designation confirmed that North Korea was behind the break-in.

A Treasury Department spokesperson said: “The United States is aware that the DPRK is increasingly relying on illicit activities – including cybercrime – to generate revenue for its weapons of destruction programs. weapons and ballistic missiles as it tries to evade US and UN sanctions.”

Lazarus has been operating for about a decade with the blessing of the North Korean government.

An FBI statement said, “The FBI continues to combat malicious cyber activity, including the threat posed by the Democratic People’s Republic of Korea to the United States and our private sector partners.

“Through our investigation, we were able to confirm that Lazarus Group and APT38, cyber actors associated with the DPRK, are responsible for the theft of $620 million from Ethereum reported on March 29.

“The FBI, in coordination with the Treasury and other U.S. government partners, will continue to expose and combat the DPRK’s use of illicit activities – including cybercrime and cryptocurrency theft – to generate income for the regime”.

Aleksander Larsen, the co-founder of Sky Mavis, which makes Axie Infinity, declined to comment.

The United States claims that the Lazarus hacking group is controlled by the Reconnaissance General Bureau, North Korea’s main intelligence office.

He has previously been accused of being involved in the WannaCry ransomware attacks in 2017 which affected 200,000 computers worldwide, including the NHS.

He is also believed to be responsible for hacking into international banks and customer accounts, as well as the 2014 cyberattacks on Sony Pictures Entertainment.

Earlier this year, the US Department of Justice announced Eun Young Choi as the first director of the National Cryptocurrency Enforcement Team.

She said, “The department has been at the forefront of investigating and prosecuting crimes involving digital currencies since their inception.

“The NCET will play a central role in ensuring that, as the technology surrounding digital assets develops and evolves, the department in turn accelerates and expands its efforts to combat their illicit misuse by criminals of all kinds.

“I am thrilled to lead NCET’s incredible and talented team of attorneys and get to work on this important priority for the department.”