North Korea-linked attackers moved millions of dollars of cryptocurrency over the weekend, according to cryptocurrency exchange Binance, in what appeared to be part of efforts to cash out the illicit gains of recent thefts. 

The funds were linked to the Horizon Bridge heist, one of North Korea’s largest scores last year.

“We detected Harmony One hacker fund movement,” Binance CEO Changpeng Zhao announced in a tweet Monday. “They previously tried to launder through Binance and we froze [their] accounts.”

Harmony One is the company behind the Horizon Bridge, which allows users to