The US government has slapped sanctions on more than a dozen companies and people it claims are involved in a commodity trading scheme to finance the Houthi rebels in Yemen.

The US Treasury says a network led by Iran’s Revolutionary Guards Corps and previously sanctioned financier Sa’id al-Jamal “has transferred tens of millions of dollars to Yemen via a complex international network of intermediaries in support of the Houthis’ attacks”.

The network has “generated tens of millions of dollars in revenue with the aid of a diverse array of international commodity traders”, the Treasury Department says in a February 23 statement.

The Houthis, who are backed by Iran, have waged a long-running guerrilla campaign against Yemen’s government. Since the outbreak of a fully-fledged civil war in 2014 the group has also launched drone and missile attacks against targets in Saudi Arabia and the United Arab Emirates.

Saudi Arabia and a coalition of Arab states that support Yemen’s government have pounded the country with air strikes that monitoring groups say have killed hundreds of civilians. US President Donald Trump designated the Houthis as a terrorist organisation, but that decision was reversed by his successor Joe Biden, who said the terrorist tag was preventing humanitarian aid to the country’s beleaguered population.

“Despite pleas to negotiate an end to this devastating conflict, Houthi leaders continue to launch missile and unmanned aerial vehicle attacks against Yemen’s neighbours, killing innocent civilians, while millions of Yemeni civilians remain displaced and hungry,” says US under secretary of the treasury for terrorism and financial intelligence Brian Nelson.

The US has announced sanctions against Abdo Abdullah Dael Ahmed, a businessman it says is based in the UAE and Sweden, and Konstantinos Stavridis, a Greek businessman also residing in the UAE.

Stavridis controls UAE business Fani Oil Trading FZE, which the US says “created fraudulent shipping documents to facilitate the sale and shipment of gasoline worth tens of millions of dollars” from al-Jamal, which was funnelled to the Houthis.

The statement says a Yemeni company controlled by Dael, Moaz Abdalla Dael Import and Export, transferred over US$10mn to al-Jamal and worked with him to channel the funds to the Houthis.

The sanctions bar US entities from transacting with the designated companies or individuals. Non-US financial institutions who engage with the companies are also at risk of being sanctioned themselves, a process known as secondary sanctions.

The blacklisted companies also include Aurum Ship Management FZC, which the US Treasury describes as a vessel manager based in India, Singapore and the UAE.

Aurum has allegedly profited from managing ships connecting to the Houthi financing network, transferring oil to Houthi-controlled ports. Its staff have “bribed [vessel] flagging authorities to ignore sanctions-evasion activities by ships” in the network, the US authorities say.

The company’s managing director Chiranjeev Kumar Singh, and a related shell company, Peridot Shipping and Trading LLC, have also been sanctioned.

Aurum’s website has recently been taken offline, but an archived version from December says it is headquartered in Sharjah and also has offices in Nigeria.

The archived website lists 17 ships in its fleet but only one, the Light Moon, was sanctioned. The US says those in charge of the vessel have turned off its automatic identification system to avoid detection while illicitly shipping petroleum products.

Its last known position was in the Red Sea, south of Jeddah, on February 18, according to vessel tracking website MarineTraffic.

Aurum could not be reached for comment. The US Treasury says that it is willing to remove entities from its list of Specially Designated Persons in order to “bring about a positive change in behaviour”.

A Turkish firm, JO General Trading Gida Sanayi Ve Ticaret and UAE-based Al Foulk General Trading Co were also blacklisted for being controlled by individuals subject to sanctions.

The UAE’s government also sanctioned Dael, his import-export firm and the Light Moon on the same day as the US announced its blacklisting, according to state news agency WAM.

Biden said in January that he is considering reapplying sanctions against the Houthis shortly after a missile strike claimed by the group killed three people working at an Abu Dhabi National Oil Company storage facility.