(UPDATE) TOKYO: One person died and seven others were missing Sunday after two Japanese navy helicopters crashed in the Pacific Ocean, officials said.

A spokesman for Japan's Self-Defense Force (SDF) confirmed the late Saturday incident to AFP and said that one person was rescued but later confirmed dead.

Defense Minister Minoru Kihara said rescuers "spotted what are believed to be part of the aircraft in the sea, and we believe that the two helicopters crashed."

"At this point the cause is unknown, but firstly we do our best to save lives," Kihara told reporters.

He said the helicopters were "doing drills to counter submarines at night."

Hours later, Kihara told reporters that the crew member who was rescued "was confirmed dead," according to the spokesman.

He also said the ministry retrieved flight recorders and was "analyzing [the cause of the incident] including possibility of a collision between the two."

The helicopters appear to have crashed during night-time training off the Izu Islands in the Pacific Ocean, broadcaster NHK reported.

Communication with one chopper was lost at 10:38 pm (1338 GMT) off the island of Torishima, and one minute later an emergency signal was received from this aircraft, NHK reported.

Around 25 minutes later, at around 11:04 pm, the military realized that communication with the other aircraft was also lost in the same area.

The Mitsubishi SH-60K helicopters from the Maritime Self-Defense Force (MSDF) are mainly based on and operate from naval destroyers.

The MSDF said as there were no other aircraft nor vessels in nearby waters, involvement of another country in the incident is unlikely, NHK added.

Japan is boosting defense spending and deepening cooperation with the United States and other countries in Asia in response to growing Chinese assertiveness in the region and an unpredictable North Korea.

Last April a Japanese army helicopter with 10 people on board crashed off Miyako island in southern Okinawa.

There were no survivors.

Two pilots, two mechanics and six crew members were on board the UH-60JA, including an army general from the 8th division.

In January 2022, a Japanese fighter jet crashed in waters off central Ishikawa region, killing two pilots on board.

And in 2019, an F-35A stealth jet crashed into the sea after taking off from northeastern Japan on a training mission.

The pilot, who died in the crash, appeared to have suffered spatial disorientation.

Last November an Osprey military aircraft belonging to the US military crashed off Japan, killing all eight people on board, in the latest of a string of fatal accidents.

This prompted a decision by the United States the following month to ground the tilt-rotor aircraft worldwide. Japan also grounded its fleet of the same aircraft.