TOKYO (AP) — Japan suspended flights of its Osprey aircraft on Thursday, officials said, a day after a U.S. Air Force Osprey plane based in Japan crashed into the sea during a training mission.

Tokyo said it had also asked the U.S. military to ground all Osprey planes operating in Japan, except those searching for victims of the crash.

A senior defense ministry official, Taro Yamato, told a parliamentary hearing that Japan had suspended Osprey flights from Thursday until details of the crash and safety were confirmed.

The US-made Osprey is a hybrid aircraft that takes off and lands like a helicopter, but in flight can turn its propellers forward and fly much faster, like an airplane.

Ministry officials said a planned training flight on Thursday at Metabaru Army Camp in Saga Prefecture in southern Japan was canceled as part of the ban on all 14 Japanese Osprey aircraft based at Japan Self-Defense Force bases.

Japanese officials said they had also asked the U.S. military to suspend all Ospreys in Japan until the crash was fully investigated and safety confirmed, except for the purpose of participating in ongoing search and rescue operations at the crash site. A U.S. osprey has joined the rescue operation since the crash, Japanese defense officials said.

“The occurrence of such a serious accident is of great concern to the people of the region and is truly regrettable,” Defense Minister Minoru Kihara told a parliamentary hearing on Thursday. “We have asked the US side to conduct flights with Ospreys stationed in Japan after confirming their flight safety,” he said. His language was vague and did not clearly state that all Ospreys should resign.

Defense officials said they hoped the U.S. side got the message, but national television NHK said a number of Ospreys had flown in and out of a U.S. air base on Okinawa.

The US Osprey crashed off the southern coast of Japan on Wednesday, killing at least one of the eight crew members. The cause of the crash and the condition of the seven others on board were not immediately known.

The Coast Guard and Japanese troops searched throughout the night, and on Thursday the Coast Guard began searching underwater using sonar at a depth of about 30 meters (100 feet) for the broken plane, which may have sunk to the seabed.

Ospreys have had a number of crashes, including in Japan, where they are used at U.S. and Japanese military bases, and the latest crash is renewing safety concerns and controversy over its use in Japan. In Okinawa, where about half of America’s 50,000 troops are stationed, Gov. Denny Tamaki said he would ask the U.S. military to halt all Osprey flights in Japan.

On Thursday, Japanese Foreign Minister Yoko Kamikawa met with U.S. Ambassador to Japan Rahm Emanuel at her ministry and called on the United States to “immediately provide information to the Japanese side.” Emanuel said the focus was now on finding the missing crew members and he thanked Japanese troops, the Coast Guard and local fishermen for standing “side by side.”

Public television NHK and other news outlets reported that the plane had requested an emergency landing at Yakushima airport about five minutes before it disappeared from radar. NHK quoted a Yakushima resident as saying he saw the plane turn upside down, fire coming from one of its engines and then an explosion before it fell into the sea.

The U.S. Air Force Special Operations Command said the CV-22B Osprey was one of six aircraft stationed at Yokota Air Base, home of U.S. Forces Japan and the Fifth Air Force, and was assigned to the 353rd Special Operations Squadron.

The plane took off from U.S. Marine Corps Air Station Iwakuni in Yamaguchi Prefecture and crashed en route to Kadena Air Base on Okinawa, Japanese officials said.

Last year, Air Force Special Operations Command ordered a temporary shutdown of its Osprey fleet after repeated safety incidents in which the Osprey clutch slipped, resulting in uneven power distribution across the rotors.

The Marine Corps and Navy have reported similar clutch slips, and each service has worked to correct the problem on its aircraft. However, clutch failure was also cited in a fatal US Marine Corps Osprey crash in 2022 that killed five people.

According to the investigation into this accident, the “double hard engagement of the clutch” caused the engine failure.

Separately, in August, a US Marine Corps Osprey with 23 Marines on board crashed on an island in northern Australia, killing three Marines and seriously injuring at least five others who were taking part in a multinational training exercise.

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Copp reported from Washington.