The U.S. military will join Japan's search and rescue efforts for seven missing Maritime Self-Defense Force members after two helicopters crashed in the Pacific over the weekend, Japanese Defense Minister Minoru Kihara said Tuesday.

The U.S. Navy will dispatch a P-8 patrol plane, Kihara told reporters, with the search areas off the Izu island chain, about 600 kilometers south of Tokyo, widening as time passes due to tides.

Kihara also said the MSDF's oceanographic research ship Shonan has been deployed to find the exact locations of the helicopters' wreckage, as the debris could have sunk deep into the sea. From the Self-Defense Forces, there are currently around 10 ships and five aircraft engaged in the search, he said.

Japanese Defense Minister Minoru Kihara holds a press conference in Tokyo on April 23, 2024, as he comments on a crash involving two Japan Maritime Self-Defense Force helicopters in the Pacific on April 20, leaving one MSDF member dead and seven others missing. (Kyodo) ==Kyodo

The accident took place during a late-night anti-submarine drill on Saturday, with two SH-60K patrol helicopters, carrying four people each, believed to have collided and crashed. One of the eight was confirmed dead the following day.

The crash site is situated in waters around 270 km east of Torishima Island in the Izu island chain, where there is a depth of about 5,500 meters.

While flight recorder data has so far not indicated any abnormalities with the helicopters prior to the crash, the choppers were found to have not been connected to an information-sharing system that would have alerted them if they had been flying too close to each other, according to a source familiar with the matter.

File photo shows flight recorders from two Maritime Self-Defense Force SH-60K patrol helicopters recovered from waters east of Torishima Island in the Izu Island chain on April 21, 2024. (Photo courtesy of the Maritime Self-Defense Force)(Kyodo)

According to the MSDF, the system allows helicopters joining anti-submarine missions to send and receive detected information. But helicopters can still operate without being connected to the system, depending on their missions and exercises.

The Defense Ministry will continue to analyze data from the two recovered flight recorders to get to the bottom of the incident. It will also hear from members who were aboard ships and other helicopters that took part in the anti-submarine drill.

On Monday, Kihara met with outgoing U.S. Indo-Pacific Command chief Adm. John Aquilino, who said the U.S. military is ready to support Japan's search activities.

The incident came as the country beefs up its defense capabilities amid China's growing maritime assertiveness, and is the latest in a string of deadly accidents involving Japan's SDF aircraft in recent years.

In April last year, a UH-60JA helicopter of the ground force crashed into waters off an island in the southern prefecture of Okinawa, resulting in the deaths of all 10 people aboard.

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