The US imposed sanctions on nine entities on Thursday over claims they have played a "critical role" in the production, sale and shipment of "hundreds of millions of dollars’" worth of Iranian petrochemicals to Asia.
The Treasury for Terrorism and Financial Intelligence released a statement on the measures put in place.
Its undersecretary Brian E Nelson said: “Iran is increasingly turning to buyers in East Asia to sell its petrochemical and petroleum products, in violation of US sanctions.”
Six of the companies are based in Iran, including Amir Kabir Petrochemical Company, which was listed by the British government in 2009 as an entity of potential concern for WMD-related procurement, according to online nuclear tracker Iran Watch.
Washington on Thursday said the Tehran-based petrochemical company had produced and sold millions of dollars’ worth of low-density polyethylene to Triliance Petrochemical Company, also under US sanctions.
Simorgh Petrochemical Company, Laleh Petrochemical, Marun Tadbir Tina, Marun Sepehr Ofogh and Marun Supplemental Industries were among the other Iranian companies in question.
The latest sanctions extended to entities outside of Iran.
Two Singapore-based firms, Asia Fuel PTE Ltd and Unicious Energy PTE Ltd, were designated over claims they "have facilitated Triliance’s sale of petroleum products to customers in East Asia".
The US Treasury Department also sanctioned Malaysia-based Sense Shipping and Trading SDN BHD, which it described as "a front company that has facilitated the shipment of tens of thousands of metric tonnes of petrochemicals for Triliance".
The new designations mean all property and interests in property of these entities that are in the US or in the possession or control of US citizens "must be blocked and reported" to the Office of Foreign Assets Control.
Additionally, any foreign financial institution that "knowingly facilitates a significant transaction" for any of companies could be subject to US sanctions, the Treasury said.
"The United States remains focused on targeting Tehran’s sources of illicit revenue, and will continue to enforce its sanctions against those who wittingly facilitate this trade,” Mr Nelson added.
