The US Treasury Department said in a statement it had blacklisted the four entities for facilitating the export of Iranian petrochemical products by Triliance Petrochemical Co Ltd, which was hit with sanctions by Washington earlier this year.
Also targeted in the move was Vietnam Gas and Chemicals Transportation Corporation over its connection with significant transactions for the transport of petroleum products from Iran, the Treasury said.
Vietnam said on Thursday it regretted the US decision to sanction the company and hoped that the US would remove the sanctions.
“Trade relations between Vietnam and Iran are strictly civilian and involve goods that would serve the essential needs of people and are not in contrary to the resolutions of the UN,” Foreign Ministry spokesman Le Thi Thu Hang told a daily briefing.
The Trump administration has imposed sanctions nearly daily over the past several weeks, many targeted at Iran.
Analysts have said the sanctions pressuring Tehran seem designed to complicate president-elect Joe Biden’s path to renegotiating a nuclear deal with Iran.
“The US will act against persons who support illicit actors engaged in the movement of Iranian petroleum and petrochemical sales,” Treasury Secretary Steven Mnuchin said in the statement.
The action placed sanctions on China-based Donghai International Ship Management Ltd, China-based Petrochem South East Limited, UAE-based Alpha Tech Trading FZE and UAE-based Petroliance Trading FZE for providing support to Triliance Petrochemical Co Ltd.
Washington in January blacklisted Hong Kong-based Triliance Petrochemical Co Ltd and three other petrochemical and petroleum companies that the Treasury said collectively transferred the equivalent of hundreds of millions of dollars’ worth of exports from the National Iranian Oil Company.
Wednesday’s sanctions froze any US assets of the companies and generally barred Americans from dealing with them.
Foreign financial institutions that knowingly facilitate transactions for those blacklisted also run the risk of being hit with sanctions, Treasury said.
Tensions between Washington and Tehran have risen since Trump abandoned President Barack Obama’s 2015 Iran nuclear deal, and restored harsh sanctions to pressure Tehran to negotiate deeper curbs on its nuclear programme, ballistic missile development and support for regional proxy forces.
President-elect Joe Biden, set to take office on Jan 20, has said he will return the US to the Obama-era deal if Iran resumes compliance.