In its latest response to attacks on shipping by the Houthis, the US on Thursday sanctioned an individual and three currency exchange houses it accused of facilitating the flow of Iranian financial assistance to the militias who have been launching attacks on commercial shipping vessels in the southern Red Sea.

Two of the exchange houses are based in Yemen and one is in Türkiye, the US Treasury Department said in a statement announcing the new measures.

“Today’s action underscores our resolve to restrict the illicit flow of funds to the Houthis, who continue to conduct dangerous attacks on international shipping and risk further destabilizing the region,” Under Secretary of the Treasury for Terrorism and Financial Intelligence Brian Nelson said in the statement.

Nelsons said the US and its allies “will continue to target the key facilitation networks that enable the destabilizing activities of the Houthis and their backers in Iran.”

The sanctions freeze any US assets belonging to the targeted entities and generally prohibit Americans from doing business with them.

Earlier this month, the US announced sanctions against 13 people and firms alleged to be providing tens of millions of dollars from the sale and shipment of Iranian commodities to the Houthis in Yemen.

The Houthis have seized or attacked with drones and missiles a dozen ships in the Red Sea and Gulf of Aden since Nov. 19.