The US sanctioned four companies associated with the shipping of Iranian oil and petrochemicals from Iran to East Asia, operations that officials said comprised tens of millions of dollars of the country’s product.

“The United States continues to pursue the path of diplomacy to achieve a mutual return to full implementation” of the 2015 accord to curb Iran’s nuclear program, Brian Nelson, the under secretary of the Treasury for Terrorism and Financial Intelligence, said in a statement. “Until such time as Iran is ready to return to full implementation of its commitments, we will continue to enforce sanctions on the illicit sale of Iranian petroleum and petrochemicals.”

The sanctioned entities include Blue Cactus Heavy Equipment and Machinery Spare Parts Trading LLC, which is based in the United Arab Emirates, and has helped facilitate the sales between Iran’s Persian Gulf Petrochemical Industry Commercial Co. and broker Triliance Petrochemical Co. Ltd., according to Treasury.

Treasury also sanctioned Farwell Canyon HK Ltd., Shekufei International Trading Co. Ltd., and Hong Kong and Malaysia-based PZNFR Trading Limited in connection with the transactions. In addition, the State Department also designated two entities: Pioneer Ship management PTE LTD and Golden Warrior Shipping, Co. Ltd.