Details on the incident were scant, but local media reported two of the wounded were in critical condition.

"Around 9.00am today, there was a shooting incident by a member of the Self-Defense at the ... Hino basic firing range and three Self-Defense Force personnel were injured," said top government spokesman Hirokazu Matsuno.

He confirmed that a suspect had been detained, but gave no further details.

National broadcaster NHK said the suspect was a teenaged member of the Self-Defense Forces, Japan's military, and had fired an automatic weapon.

The station also reported that one of those wounded was unresponsive.

Violent crime in Japan is extremely rare, but several high-profile incidents have rattled the country over the last year.

In July 2022, former prime minister Shinzo Abe was shot dead on the campaign trail by a man who allegedly targeted him over his links to the Unification Church.

And in April, Prime Minister Fumio Kishida escaped unharmed after a man threw an explosive device towards him at a campaign event.

Security has been tightened in the wake of the incidents, particularly around last month's G7 leaders' summit in Hiroshima, which saw thousands of police deployed.

Last month, police also detained a man accused of killing four people, including two police officers, in a knife and gun attack in Nagano west of Tokyo.