The US has imposed new sanctions on a network of people and companies linked with the trade in Iranian oil that generates funds for regional proxy groups including those accused of attacks on shipping.

The measures have been imposed against 21 people and groups involved in the “intricate networks of foreign-based front companies and brokers to enable these illicit commercial activities”.

They included brokers and traders based in Iran, the United Arab Emirates and Hong Kong, according to the US Department of the Treasury.

UAE-based CGN Trade FZE worked with the company of a sanctioned Turkish businessman to load at least 10 tankers with Iranian oil on behalf of the Islamic Revolutionary Guard Corps-Qods Force (IRGC-QF), said the Treasury.

Iran's IRGC-QF is the main body that supports proxy groups outside of Iran, say analysts.

“Iran’s commodity sales, carried out through a network of foreign-based front companies, provide revenue that helps the regime to continue its support for terrorist groups such as Hamas and Hezbollah,” said a State Department spokesman.

The US said the Iranian government allocated billions of dollars of commodities to Iranian military bodies that sell them to foreign buyers to generate revenue for their overseas activities.

One named Iranian front company, the Sepehr Energy Jahan Nama Pars Company, shipped oil using the National Iranian Tanker Company, which was sanctioned by the US in 2020, it said.

Sepehr was said to use companies in Hong Kong and the UAE to sell oil to customers in Europe and East Asia. Some of it was marketed as Malaysia-origin to hide where it came from, according to the sanctions notice.

The move by the US comes after some critics had accused the Biden administration of easing off from Iranian-linked action to ensure global oil kept flowing amid the upheavals of Russia’s invasion of Ukraine and production cuts.

Concerns have been mounting over the actions of groups funded by Iran including the Yemen-based Houthi group that seized 5,100-ceu car carrier Galaxy Leader (built 2022) earlier this month.

The Houthis have relied on support from the IRGC-QF since the war started in Yemen in 2014, according to the US.

The International Chamber of Shipping has called for an end to attacks on ships in the Red Sea and Gulf of Aden amid rising tensions following the surprise attack by Hamas on Israel last month and Israel’s response in Gaza.