Yemeni fighters from the Houthi movement said they will block Saudi Arabia’s coast starting Monday. Their spokesman, Yahya Saree, called it a maritime strike. Cargo vessels moving through the Red Sea near Saudi ports might see postponements. U.S. warplanes continued striking targets after their warning. The group took several ships. Insurers now see Red Sea routes as hazardous. Traders are holding their breath, watching for higher fees or diverted shipments. Saudi ports border the risk area, so any carries swift impact.