The Justice Department unsealed an indictment on Thursday accusing North Korea’s state-owned bank of conspiring with nearly three dozen individuals to process over $2.5 billion in illegal payments for the country’s nuclear weapons and missile program. U.S. prosecutors have charged 28 North Koreans and five Chinese nationals in the vast money laundering scheme allegedly led by the Foreign Trade Bank, which was sanctioned in 2013 and barred from making any transactions with U.S. entities. The 33 agents allegedly used “over 250 front companies” around the world to evade sanctions and illegally process payments “transited through the United States,” the indictment reads.

The Foreign Trade Bank allegedly operated covert branches in countries such as Thailand, China, Russia, and Austria to funnel the money through an international system. Top U.S. officials told The Washington Post that the indictment marks the largest North Korea sanctions violation case in history.