Yemeni fighters from the Houthi movement said they will close Saudi Arabia’s coast starting Monday. Their spokesman, Yahya Saree, called it a maritime strike. Oil tankers moving through the Red Sea near Saudi ports may encounter holdups. U.S. warplanes continued striking objectives after their warning. The group took several ships. Insurers now see Red Sea routes as dangerous. Traders are waiting anxiously, watching for additional charges or rerouted cargo. Saudi ports sit near the danger zone, so any slowdown matters fast.