Iran has reportedly instructed the Houthi militia in Yemen to prepare to close the Bab el-Mandeb Strait, a vital Red Sea shipping gateway, should the United States strike Iranian power infrastructure, according to Reuters. The move comes amid intensifying US military action against Iran, now in its 13th consecutive night of strikes, and raises fears of a wider regional conflict that could disrupt global shipping and energy markets.

The threat follows reports that vessels have been targeted by Iranian drones since March, and separately Iran has also threatened to close the Strait of Hormuz, a move that has already pushed crude oil prices down by around 2% amid market uncertainty. US Secretary of State Marco Rubio has accused Iran of flying Islamic Revolutionary Guard Corps personnel into Yemen to bolster the Houthi threat, while President Trump has warned of a "massive attack" against Iran. Experts are questioning whether the Houthis have the practical capability to actually close the strait despite Tehran's instructions.