North Korean hackers were allegedly responsible for the theft of $100 million in digital assets from a US crypto firm last year, according to US law enforcement.

The North Korean hacking groups Lazarus Group and APT38 were accused of being behind the cyber heist on crypto firm Harmony last June, according to an FBI statement released on Monday.

The FBI accused North Korean cyber actors of using the privacy protocol Railgun earlier this month to launder more than $60 million in Ethereum stolen during the heist, a portion of which was reportedly sent to several virtual asset service providers and converted to Bitcoin.

Harmony, based in California, announced in June that hackers had stolen $100 million in digital coins from Horizon bridge, a blockchain bridge used to transfer cryptocurrencies between different blockchain networks.

The FBI said it had frozen some of the funds with the help of some virtual asset service providers.

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According to the statement, the FBI plans to keep working to “identify and disrupt” alleged attempts by the DPRK to steal cryptocurrency to support its nuclear weapons program. “The FBI will continue to expose and combat the DPRK’s use of illicit activities — including cybercrime and virtual currency theft — to generate revenue,” the FBI said.

North Korea, which for years has been under crippling Western sanctions, has been accused by US and UN officials of orchestrating an escalating campaign of "cyber theft to fund its activities," including the development of long-range ballistic missiles and nuclear weapons.

Seoul claims DPRK hackers stole $1.2bln

Hackers from the Democratic People's Republic of Korea (DPRK) have allegedly stolen over 1.5 trillion won ($1.2 billion) worth of bitcoin and other virtual assets over the previous five years, South Korea's intelligence service claimed on December 24, further alleging that more than half of the attacks in question took place last year.

South Korean officials say that the DPRK, in light of the UN sanctions and the COVID-19 pandemic, has become reliant on crypto hacking and other operations carried out in cyberspace to fund its economy that has been hit by sanctions from all sides.

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The UN sanctions imposed on the Korean people back in 2016-2017 banned important exports from the DPRK, such as coal, textiles, and seafood, and forced member nations to deport DPRK citizens who had been working abroad. After enacting highly strict restrictions to combat the spread of COVID-19, the DPRK's economy experienced significant blows.