China's participation in the Rim of the Pacific exercises comes amid tensions at sea with neighbors ranging from Vietnam and the Philippines to the south, to Japan in the east.
Twenty-three countries are expected to participate in this year's drills, including Canada, India, Japan and South Korea. The exercises begin June 26 and last through Aug. 1
State media said Tuesday that the destroyer Haikou, missile frigate Yueyang, the oiler Yueyang, and hospital ship Peace Ark departed their various home ports on Monday. They are carrying 1,100 officers and sailors, including a commando unit and diving team, along with two helicopters.