U.S. naval planners are scrambling to deal with what analysts say is a game-changing weapon being developed by China — an unprecedented carrier-killing missile called the Dong Feng 21D that could be launched from land with enough accuracy to penetrate the defenses of even the most advanced moving aircraft carrier at a distance of more than 1,500 kilometers (900 miles).

"China can reach out and hit the U.S. well before the U.S. can get close enough to the mainland to hit back," said Toshi Yoshihara, an associate professor at the U.S. Naval War College. He said U.S. ships have only twice been that vulnerable — against Japan in World War II and against Soviet bombers in the Cold War.