Five individuals who helped North Korean information technology (IT) workers secure jobs at U.S. companies have pleaded guilty to charges of wire fraud and identity theft, as Washington continues its crackdown on the illicit activities funding Pyongyang’s weapons programs.

The individuals helped Pyongyang defraud at least 136 American companies and generate more than $2.2 million in revenue over several years, compromising more than 18 U.S. nationals’ identities in the process, the Department of Justice (DOJ) said in a press release on Friday.