Iran on Tuesday slammed as "destructive" new US sanctions targeting its crucial energy sector and vowed a response, at a time when nuclear talks have stalled for months.
US President Joe Biden's administration "is not stopping this unproductive and destructive action even at a time when efforts are underway to resume negotiations to revive the Iran nuclear deal," said foreign ministry spokesman Nasser Kanani.
Iran will "show a firm and immediate response" to the sanctions announced the previous day and "take all necessary measures to neutralise" their potential impacts on the country's trade, Kanani vowed in a statement.
The US government blacklisted six companies Monday that it said helped Iran export petrochemicals to East Asia in avoidance of sanctions over Tehran's nuclear programme.
Three Hong Kong-based trading companies and one United Arab Emirates firm were hit with US Treasury sanctions for helping Iran's Persian Gulf Petrochemical Industry Commercial Co. ship "millions of dollars worth" of petroleum and petrochemical products to unnamed East Asian buyers, the Treasury said.
In addition, the US State Department blacklisted two shipping firms, based in China and Singapore, for helping arrange the shipments.
The sanctions block any assets the entities own under US jurisdiction and ban US persons or entities from doing business with them, effectively constricting their access to the global financial system.
The move came as talks in Vienna between Iran and several major powers, including the United States, to revive the frayed 2015 international agreement on the Iranian nuclear programme have been at a standstill since March.
Last Tuesday, EU foreign policy chief and coordinator of the nuclear talks between Iran and world powers, Josep Borrell, submitted a new draft text and urged all sides to accept it or "risk a dangerous nuclear crisis".
Kanani criticised the Biden administration for "continuing and even expanding" the "failed" policies of his predecessor Donald Trump, who unilaterally withdrew the United States from the nuclear deal in 2018.
Tehran, for its part, has been gradually backing away from its obligations.
Iran had expressed "optimism" on Monday that the nuclear talks would resume after Borrell's draft compromise was reviewed.
