North Korean cybercriminals are prime suspects in a recent cryptocurrency heist involving the theft of a substantial amount of $35 million. Cybersecurity analysts shared this assessment with CNN on Tuesday, noting telltale signs in the tactics and techniques used in the attack.

The victim of the heist, Atomic Wallet, a widely used cryptocurrency service based in Estonia, reportedly suffered a breach of customer accounts over the weekend. While the company acknowledged the incident, stating that it affected “less than 1%” of its monthly users, it has yet to comment on the total losses suffered or identify the culprits.

The aftermath of the incident has seen victims appeal directly to the thieves on Twitter, hoping for some semblance of mercy. They posted their cryptocurrency addresses and pleaded for the return of the stolen funds.

Although the total amount stolen remains unconfirmed, independent cryptocurrency analyst ZachXBT suspects it could exceed $35 million as Atomic Wallet continues to conduct its investigation.

“We’re seeing some striking similarities between this and previous attacks attributed to North Korean hackers,” he told CNN. “This includes the Harmony case earlier this year, which involved the laundering of around $100 million.”

Indeed, Pyongyang-linked cybercrime has been a growing concern, as North Korean hackers are allegedly responsible for siphoning billions of dollars from banks and cryptocurrency firms in recent years. Some reports, including those from the United Nations, suggest that this illicit activity is a major source of revenue for North Korea’s isolated regime.

The US administration is well aware of the potential implications for national security. A White House official shared last month that nearly half of the funding for North Korea’s missile program can be traced to these cybercrime activities.

In response to this evolving threat landscape, the Biden administration is shifting its focus toward strengthening defenses against these cyberattacks and reducing money laundering activities. As part of this initiative, it is partnering with allies and private companies globally to increase the resilience of the financial system and disrupt resources flowing into North Korea’s missile program.

Meanwhile, the FBI has been alerted to the Atomic Wallet hack and is expected to join the ongoing investigation. The goal is to discover the culprits, trace the stolen funds and prevent future incidents of this nature.