The Apache helicopter that crashed into the sea the previous day was shot down by Iran while patrolling over the Strait of Hormuz, President Trump said Tuesday, vowing to "respond to this attack." "There were two pilots involved, both are safe and uninjured," Mr. Trump wrote. "Nevertheless, the United States must, of necessity, respond to this attack." The two crew members were rescued by a sea drone in the first such operation ever carried out by the U.S. military, officials told CBS News. The surface drone rescued the soldiers and transported them to another location on the water where they were then hoisted up to a helicopter for further transport, according to a U.S. official. The two U.S. Army soldiers on the Apache had been patrolling waters off the coast of Oman when the crash happened. They were rescued at about 7:30 p.m. Eastern time on Monday, "within approximately two hours" of their AH-64 Apache going down.