Two Japanese Maritime Self-Defense Force helicopters crashed during a drill in the Pacific late Saturday, leaving at least one of the eight crew members dead, with the other seven still missing, Japan's defense minister said.

The two aircraft, which crashed in waters around 270 kilometers east of Torishima Island in the Izu Island chain during a nighttime anti-submarine drill in the area, are believed to have collided with each other, Defense Minister Minoru Kihara told reporters Sunday. The Izu Islands are located south of Tokyo.

The crash added to a series of fatal accidents including Japanese Self-Defense Forces aircraft in recent years, fueling public concern over the safety of their flights despite the government's efforts to sharply increase defense spending.

File photo shows an SH-60K helicopter of the Maritime Self-Defense Force. (Photo courtesy of the MSDF) (Kyodo)

"We have been providing education to ensure that lessons from past incidents are not forgotten, but this kind of accident has occurred, so it is a matter of the greatest regret," Kihara said, recognizing the frequency of accidents within the SDF.

The SH-60K helicopters, each carrying four crew members, lost contact at 10:38 p.m. and 11:04 p.m., respectively, with the MSDF receiving an emergency signal at 10:39 p.m., according to the MSDF.

Photo taken from a Kyodo News plane on April 21, 2024, shows a Japan Maritime Self-Defense Force ship searching for two MSDF helicopters in waters east of Torishima Island in the Izu Island chain in the Pacific after they crashed during a drill the night before, leaving at least one of the eight crew members dead, with the other seven missing. (Kyodo) ==Kyodo

The emergency signal was possibly emitted from the two choppers simultaneously on the same wavelength, Kihara said.

Two flight recorders were recovered "at extremely close locations" and are now under analysis, while what appears to be rotor blade parts from the two helicopters and other aircraft debris was also found during a post-accident search, he said.

Following the accident, the MSDF suspended all training involving SH-60K helicopters, made by Mitsubishi Heavy Industries Ltd., and set up a panel to investigate the incident, according to Adm. Ryo Sakai, chief of staff of the MSDF.

Together with another MSDF helicopter, the two crashed aircraft were conducting an exercise to detect and attack a submarine, after taking off from separate destroyers that were deployed near the incident site, Sakai told a press conference.

Sakai said no abnormality in the equipment of the two aircraft has been reported, adding that the water depth near the crash site is about 5,500 meters.

Japanese Defense Minister Minoru Kihara speaks to reporters at the Defense Ministry in Tokyo on April 21, 2024. (Kyodo)

One of the choppers belonged to Komatsushima Air Base in Tokushima Prefecture, while the other was based at Omura Air Base in Nagasaki Prefecture.

The cause of the accident is still unknown, but the ministry will do its utmost to search for and rescue those who are missing, Kihara said.

With a length of 19.8 meters and a weight of 10.9 tons, the MSDF's SH-60K can carry up to four people and has its own anti-submarine system, modeled after the U.S. Navy's SH-60 chopper.

Recent deadly incidents by SDF aircraft include a crash of a UH-60JA helicopter of the Ground Self-Defense Force into the sea in Okinawa Prefecture in April 2023, resulting in the deaths of all 10 people aboard.

In January 2022, an Air Self-Defense Force F-15 fighter jet crashed into the Sea of Japan off Ishikawa Prefecture in the central part of the country, killing two pilots.

Adm. Ryo Sakai, chief of staff of the Japan Maritime Self-Defense Force, holds a press conference in Tokyo on April 21, 2024, after two MSDF helicopters crashed during a drill in the Pacific the night before, leaving at least one of the eight crew members dead, with the other seven missing. (Kyodo) ==Kyodo

Under its war-renouncing Constitution, Japan had long capped its annual defense budget at around 1 percent of its gross domestic product, or about 5 trillion yen ($32 billion).

But the government pledged in 2022 to almost double it to 2 percent or more in five years through March 2028, amid growing security challenges such as China's military buildup and North Korea's nuclear and missile development programs.

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