The US air force has recovered the remains of six of the eight service members who were lost when their Osprey crashed off the coast of Japan last week.

Efforts will now focus on recovering the two bodies still missing and the aircraft debris, Air Force Special Operations Command said.

The CV-22B Osprey crashed on November 29 during a training mission.

Ospreys have had a number of crashes, including in Japan, where they are used at US and Japanese military bases, and the latest has rekindled safety concerns.

Three bodies were recovered from the sunken wreckage, and a total of six of the eight crew members’ remains that had been located have now been recovered, the US air force said. The search continues for the remains of the two crew members still unaccounted for.

Lt Gen Tony Bauernfeind said: “The depth of sorrow is immeasurable.

Crash debris
Debris believed to be from a US military Osprey aircraft is seen off the coast of Yakushima Island in Kagoshima (Japan Coast Guard via AP)

“The honourable service of these eight airmen to this great nation will never be forgotten, as they are now among the giants who shape our history.”

US President Joe Biden said he and first lady Jill Biden were heartbroken by the loss.

“We owe them everything,” Mr Biden said in a statement. “Jill and I are praying for the families and friends who lost a loved one in this terrible accident.”

The lost crew members were:

Maj Jeffrey T Hoernemann, 32, of Andover, Minnesota; Maj Eric V Spendlove, 36, of St George, Utah; Maj Luke A Unrath, 34, of Riverside, California; Capt Terrell K Brayman, 32, of Pittsford, New York; Tech Sgt Zachary E Lavoy, 33, of Oviedo, Florida; Staff Sgt Jake M Turnage, 25, of Kennesaw, Georgia; Senior Airman Brian K Johnson, 32, of Reynoldsburg, Ohio; Staff Sgt Jacob “Jake” M Galliher, 24, of Pittsfield, Massachusetts.

Japanese Prime Minister Fumio Kishida sent a message to Mr Biden, offering his heartfelt condolences to the families of those who were lost and to the American people and his thanks for their dedication away from home for the peace and stability of Japan and the region.

The US-made Osprey is a hybrid aircraft that takes off and lands like a helicopter but can rotate its propellers forward and cruise much faster, like a plane, during flight.

The cause of the crash is under investigation.

Japan has suspended all flights of its own fleet of 14 Ospreys. Japanese officials say they have asked the US military to resume Osprey flights only after ensuring their safety. However, the Pentagon said no such formal request has been made and that the American military is continuing to fly 24 MV-22s, the Marine version of Ospreys, deployed on the southern Japanese island of Okinawa.

Adm Ryo Sakai, chief of staff of the Japanese navy, pledged continued support for the search and recovery operation.