White House Press Secretary Sean Spicer has vowed the United States would take a hard military line against China in the South China Sea, one of the busiest trade routes in the world, which also has significant oil and gas reserves. The U.S. claims the area is international water, while China claims territorial control. Longtime ExxonMobil CEO Rex Tillerson said during his confirmation hearing for secretary of state that he would stop China from accessing islands where it has installed weapons systems and built air strips in the area. Tillerson’s comments prompted Chinese state media to say the U.S. would have to “wage war” to stop China from accessing the islands.