The Houthis said on Tuesday that they would target major US oil companies, including ExxonMobil and Chevron, despite a previous truce with the administration of US president Donald Trump that prohibited attacks on vessels linked to the United States sailing in the Red Sea and the Gulf of Aden.

The Humanitarian Operations Coordination Centre (HOCC), based in Sanaa, announced that it had placed 13 American companies, nine individuals and two vessels on its sanctions list. The centre acts as a linkage between Houthi forces and commercial shipping companies, and is closely connected with Houthi military units.

On its website, the centre stated that the entities placed on the sanctions list “will be dealt with under the principle of confrontation.”

The announcement serves as a warning to the companies involved, including ConocoPhillips and Diamond S Shipping, that they are considered hostile and at risk of attack.