TOKYO (AP) — A Marine refueling plane and a fighter jet crashed into the Pacific Ocean off Japan’s southwestern coast after colliding early Thursday, and rescuers found two of the seven crew members, one of them in stable condition, officials said.

The U.S. Marine Corps said that the 2 a.m. crash involved an F/A-18 fighter jet and a KC-130 refueling aircraft during regular refueling training after the planes took off from their base in Iwakuni, near Hiroshima in western Japan.

The crash took place 200 miles off the coast, according to the U.S. military. Japanese officials said it occurred closer to the coast, about 100 kilometers (60 miles), and that’s where the search and rescue mission found two crew members.

The two aircraft were carrying seven crew members in total, two in the F/A-18 and five others in the KC-130, when they collided and crashed into the sea south of the Muroto Cape on Shikoku island in southwestern Japan. The cause of the crash is under investigation.

The Maritime Self-Defense Force, which dispatched aircraft and vessels to join in the search operation, said Japanese rescuers found one of the crew from the fighter jet in stable condition. The Marines said that the rescued crew was taken to a hospital on the base in Iwakuni, but did not provide any other details.

Details of the second crew, including his or her condition, were unknown immediately.

The crash is the latest in recent series of accidents involving the U.S. military deployed to and near Japan.

Last month, a U.S. Navy F/A-18 Hornet from the aircraft carrier USS Ronald Reagan crashed into the sea southwest of Japan’s southern island of Okinawa, though its two pilots were rescued safely. In mid-October, a MH-60 Seahawk also belonging to the Ronald Reagan crashed off the Philippine Sea shortly after takeoff, causing non-fatal injuries to a dozen sailors.

More than 50,000 U.S. troops are based in Japan under the bilateral security pact.