"Iran must stop exploiting its natural resources to fund terror and destruction across the region," US Secretary of State Mike Pompeo warned in a tweet.

It was the latest in a series of sanctions that Washington has slapped on foreign companies doing business with Tehran.

US President Donald Trump in 2018 pulled out of the international agreement signed with the country to prevent it from acquiring nuclear weapons, which he said was ineffective, and immediately re-established and tightened US sanctions against the Islamic Republic.

The US State Department imposed punitive measures on Iran-based Abadan Refining Company, three China-based companies (Zhihang Ship Management CO Ltd., New Far International Logistics LLC, Sino Energy Shipping Ltd) and another based in the UAE (Chemtrans Petrochemicals Trading LLC). Three executives from Abadan, New Far and Sino Energy were also targeted.

Meanwhile, the US Treasury Department has added to its blacklist six firms also based in those countries for doing business with Triliance Petrochemical, a company sanctioned in January for its involvement in the sale of Iranian petrochemical products.

Treasury said those funds are "a key revenue source for the Iranian regime, helping to finance its destabilizing support to corrupt regimes and terrorist groups throughout the Middle East and, more recently, Venezuela."

The newly blacklisted companies are the Iranian firms Zagros Petrochemical Company, UAE-based Petrotech FZE and Trio Energy DMCC, and Chinese companies Jingho Technology Co. Limited, Dynapex Energy Limited and Dinrin Limited, based in Hong Kong.