 The U.S. and South Korean naval ships conducted joint drills in international waters off the southern island of Jeju on March 27, South Korea's Navy said. The drills were designed to improve the execution of U.S. extended deterrence its military capability, especially nuclear forces, to deter attacks on its allies by deploying American strategic assets amid the North's growing threats, a South Korean Navy official said. A U.S. carrier strike group led by the USS Nimitz joined the military exercises with South Korea. The aircraft carrier is scheduled to dock at a South Korean naval base in the southeastern port city of Busan on March 28. The drill came as North Korea fired two short-range ballistic missiles into the sea off its east coast on Monday morning. Cheon Yang has long bristled at the allies' drills, saying they are preparation for an invasion of the North.