A Red Sea blockade threatens a new front in U.S.-Iran war, potentially choking off a key oil shipping route.

Tehran and Washington are doubling down on their standoff over the Strait of Hormuz, as a Red Sea blockade risks shutting another key shipping route amid an expanding war. The Iran-backed Houthis in Yemen announced a blockade on Saudi Arabia's shipments through the Red Sea's Bab al-Mandeb Strait, which, if successful, could choke off one of the Gulf's few viable alternatives for oil exports and reduce global supply by an estimated 7 percent.