Yemeni fighters from the Houthi movement said they will seal off Saudi Arabia’s coast starting Monday. Their spokesman, Yahya Saree, described it as naval attack. Oil tankers moving through the Red Sea near Saudi ports could face delays. U.S. warplanes kept hitting objectives after their warning. The group seized several ships. Insurers now see Red Sea routes as risky. Traders are holding their breath, watching for extra costs or alternative loads. Saudi ports are close to the risk area, so any delay is critical quickly.