U.S. official : The U.S. is `` advising '' air carriers to `` comply '' with U.S. 's request . Since then , there 's been no backing down . It 's `` for safety , '' even if the China does n't recognize China 's new air defense zone . China says 10 U.S. military planes , 10 Chinese military planes entered disputed zone . The zone is part of a rapidly escalating dispute over the East China Sea territory .
U.S. official : The U.S. is `` advising '' air carriers to `` comply '' with U.S. 's request . It 's `` for safety , '' even if the China does n't recognize China 's new air defense zone . China says 10 U.S. military planes , 10 Chinese military planes entered disputed zone . The zone is part of a rapidly escalating dispute over the East China Sea territory .