WASHINGTON — A sailor from the destroyer Stethem is missing in the South China Sea, U.S. Pacific Fleet confirmed Tuesday, triggering a search-and-rescue operation inside the contested waters. 

The sailor was reported missing at 9 a.m. local time on Tuesday. The Japan Maritime Self-Defense Force destroyer Sazanami and helicopter carrier Izumo were assisting in search-and-rescue efforts early Wednesday morning local time, U.S. Pacific Fleet said. 

Joint Personnel Recovery Center Hawaii is also assisting in the search.

This is the second major search-and-rescue effort in the Asia-Pacific region this summer. The first one in June ended after a 50-hour search off Okinawa, only to discover days later the the missing sailor had been hiding in the engineering spaces.

The Navy lost a sailor earlier in June off the cruiser Normandy off the coast of North Carolina.