Correction at 1330 KST: This article has been corrected to reflect the fact that Namgang Construction, not Namgang Trading, was sanctioned in 2016.

The U.S. Treasury Department has blacklisted two companies — one Chinese, one North Korean — for violating a global ban on DPRK citizens working overseas, the department announced on Tuesday.

According to the statement, the Korea Namgang Trading Corporation, based in Pyongyang, and Beijing Sukbakso, allegedly collaborated to send North Korean workers to Russia, Nigeria, and multiple countries in the Middle East — despite American and United Nations sanctions prohibiting DPRK laborers from earning money abroad.