Two Maritime Self-Defense Force (MSDF) helicopters crashed late Saturday during nighttime training near the Izu Islands, killing at least one crew member and leaving seven missing, with the two aircraft believed to have collided, Defense Minister Minoru Kihara said.

Speaking at a televised news conference Sunday morning, Kihara said that a crew member who had been found has been pronounced dead.

"I am very sorry that the situation has come to this point," he said. "As for the other seven, we are doing our best to find and rescue them."

The identity of the deceased was not immediately released, but Kihara said later Sunday that the body had been transferred to a hospital in Yokosuka, Kanagawa Prefecture, for examination.

Kihara said that the cause of the crash was being probed after the two SH-60K helicopters' flight recorders were found and recovered in close proximity to each other, with the defense chief saying that the ministry had determined "that there is a high possibility of a collision."

Training flights with the SH-60K helicopters — which are mainly operated from destroyers — have been suspended, he added.

The recovered flight recorders were transported to a team responsible for their analysis at the MSDF’s Atsugi base in Kanagawa Prefecture.

MSDF Chief of Staff Adm. Ryo Sakai told a news conference later Sunday that an investigation committee had been created to probe the crash.

“We will analyze the cause of the accident and strive to prevent a recurrence,” Sakai said, adding that he had canceled his trip to China for a regional naval conference in order to deal with the matter.

Sakai said that at the time of the crash, three of the helicopters had been conducting anti-submarine training exercises involving searching, detecting and mock attacking submarines operated by the MSDF.

"We believe it is highly probable that the two aircraft collided midair during the nighttime operations,” he said, noting that it was not yet clear if the helicopters had experienced any equipment abnormalities.

He said that members aboard the other unharmed aircraft may have witnessed the collision and that officials were interviewing the crew of that aircraft.

Visibility is often poor during nighttime anti-submarine training, Sakai said, noting that “there are times when the distance between helicopters is very close,” though pilots are told to ensure safe distances are maintained.

“However, in this case, where there was a high probability of a collision, I believe that how the separation distance or watch was conducted is a major issue for the investigation into the accident’s cause,” Sakai said.

Sakai revealed Lt. Cmdr. Takuya Matsuda, of the Omura Air Base in Nagasaki Prefecture, and Lt. Cmdr. Kazuki Itamura, from the Komatsushima Air Base in Tokushima Prefecture, were the captains of the two crashed aircraft, adding that they were accompanied by one co-pilot and two aviation officers on each aircraft.

Other than the flight recorders, fragments of one of the helicopter's blades and fuselage, as well as several helmets belonging to crew members, have been recovered.

Contact was lost with the helicopters, each carrying four crew, in an area about 270 kilometers east of Torishima in the Izu Island chain during the anti-submarine training drills at 10:38 p.m. and 11:04 p.m., respectively.

The MSDF said that after contact was lost with the first helicopter, an emergency signal had been received from the aircraft a minute later. Some 25 minutes on, it was noticed that communication with the other helicopter had been lost in the same area.

Kihara said earlier that no other vessels or aircraft, including from other countries, were detected in the waters nearby, and that outside involvement was unlikely.

There were no advisories or warnings issued for the southern Izu Islands or the Ogasawara Islands on Saturday night around the time of the drill, NHK reported, citing the Meteorological Agency, adding that there was a possibility of cloud cover around Torishima based on satellite imagery.

Due to a lack of radar coverage from Torishima to the vicinity of the Ogasawara Islands, it's unclear whether it was raining near Torishima at the time.

The area near Torishima consists of uninhabited islands, something that could make the search and rescue effort more difficult considering the remoteness of the crash site — some 600 km south of Tokyo.

Eleven MSDF ships and five aircraft — four helicopters and one fixed-wing aircraft — as well as two Japan Coast Guard vessels and an aircraft, were involved in the search and rescue operation, according to the Defense Ministry.

The waters where they sank are around 5,500 meters deep, which could also complicate search efforts.

“We consider this operation to be far from easy,” Sakai said.

The U.S. military has also offered to help in the search and rescue effort, U.S. Ambassador to Japan Rahm Emanuel posted to his X social media account.

“We will stand together, side by side, with our friend and ally, Japan,” he wrote.

The Self-Defense Forces have ramped up joint training both between the services and with other militaries in recent years amid rising concerns over China’s growing assertiveness in the waters and skies near Japan.

Tokyo has been especially concerned about an emergency involving democratic Taiwan, which China considers a renegade province that must be unified with the mainland, by force if necessary. Top Japanese officials have repeatedly stressed that any conflict over Taiwan would also represent an existential crisis for Japan.

Skipping training or reducing its frequency without improving operational capabilities could lead to another level of risk in the event of an emergency, Kihara said.

In July 2021, a collision occurred between an MSDF SH-60K and a SH-60J helicopter off the coast of Amami-Oshima in Kagoshima Prefecture during a nighttime training session.

At the time, both helicopters sustained damage to one rotor blade each, but the crew were able to return to their destroyer on their own, and there were no injuries.

The crash also comes just over a year after a Ground Self-Defense Force UH-60JA helicopter crashed off Miyako Island in Okinawa Prefecture, killing all 10 people on board.