In the latest incident involving the American military in Asia, a U.S. Navy C2-A transport plane carrying 11 crew members and passengers crashed into the ocean about 900 km southeast of Okinawa, leaving three missing after eight were rescued.

The aircraft had been on a “routine transport flight” carrying passengers and cargo from Marine Corps Air Station Iwakuni in Yamaguchi Prefecture to the USS Ronald Reagan aircraft carrier, which was conducting joint drills with the Maritime Self-Defense Forces in the Philippine Sea, when it crashed.

The rescued personnel were transferred to the aircraft carrier for medical evaluation and were in “good condition,” the U.S. Navy’s 7th Fleet said in a statement.

Search and rescue efforts for the three missing passengers were continuing with U.S. Navy and MSDF ships and aircraft on the scene, it added.

“Our entire focus is on finding all of our Sailors,” said Rear Adm. Marc H. Dalton. “U.S. and Japanese ships and aircraft are searching the area of the crash, and we will be relentless in our efforts.”

Japanese Defense Minister Itsunori Onodera had earlier told reporters that the U.S. military had said the cause of the crash appeared to be engine trouble. The C2-A is a twin-engine, high-wing aircraft that provides logistics support to carrier strike groups.

No members of Self-Defense Forces were aboard the plane, Kyodo News quoted Onodera as saying. The 7th Fleet said the names of the crew and passengers aboard the plane were being withheld pending next of kin notification.

The 7th Fleet said the crash would be investigated.

The Reagan is home-ported at the U.S. naval base in Yokosuka, Kanagawa Prefecture.

The 7th Fleet has seen two fatal accidents in Asian waters this year, leaving 17 sailors dead and prompting the removal of eight top navy officers from their posts, including the 7th Fleet commander.

The USS John S. McCain, also home-ported in Yokosuka, collided with an oil tanker near Singapore in August, leaving 10 U.S. sailors dead. Seven other sailors were killed in June after the Yokosuka-based USS Fitzgerald and a container ship collided south of Tokyo Bay.

The U.S. Navy said in a damning report earlier this month that the collisions were “avoidable,” faulting leadership shortcomings and an erosion of sailors’ basic standards. It also cited the crews’ grueling schedule and resulting fatigue as contributing to the accidents. The report recommended a number of changes to address the issues, including improvements in training and stress management for sailors.

Staff writer Tomohiro Osaki contributed to this report