Five US marines are missing after two aircraft crashed during a refuelling operation off the coast of Japan, according to a US defence official.

The planes, which are thought to have been involved in a midair collision, were an FA-18 Hornet jet fighter and a KC-130 Hercules refuelling aircraft, the official said. Japan’s defence ministry said its maritime self-defence forces had rescued one of the seven people aboard the two aircraft.

In a statement, the Marine Corps said the planes had taken off from an air station at Iwakuni, west of Hiroshima, at around 2am local time, and were conducting regularly scheduled training exercises when a “mishap” occurred about 200 miles off the Japanese coast.

Japanese search and rescue aircraft have reportedly taken the lead in the rescue mission. “We are thankful for the Japan maritime self-defence force’s efforts as they immediately responded in the search and rescue operation,” the Marine Corps said.

US media initially reported five crew were on the C-130 and two on the FA-18.

One crew member had already been rescued and is thought to be in a stable condition, Takeshi Iwaya told reporters.

A spokesman for the Japanese Self-Defense (SDF) said another crew member had been found but there were no immediate details of the marine’s condition.

A Japanese official said Japan had scrambled four aircraft and three ships in the search.

About 50,000 US military personnel are based in Japan, and accidents are not uncommon.

Last month, a US navy fighter jet from the aircraft carrier USS Ronald Reagan crashed into the sea off Japan’s southern island of Okinawa. Its two crew members were rescued alive.

In October, a MH-60 Seahawk crashed on the Ronald Reagan’s flight deck shortly after takeoff in the Philippine Sea, injuring a dozen sailors.

The US military has also experienced difficulties with its Osprey helicopters, with several emergency landings, a deadly crash and a piece of the chopper falling on the grounds of a Japanese school.

The Guardian