The Biden administration has put the Houthi militant organisation back on the US government’s list of official terrorist groups, spurred on by continued attacks on shipping.

The move to name Ansar Allah, as the Houthi movement is officially known, as a “specially designated global terrorist” comes just under three years after the US State Department removed the designation as a way to speed up humanitarian to aid to war-torn Yemen, where the militants have control of a major swathe of the country.