A special tactics airman assigned to the 353rd Special Operations Wing waits for instruction to hoist a patient up a slope during a mass casualty exercise at Kadena Air Base, Okinawa, in October 2022. (Tylir Meyer/U.S. Air Force)

The Air Force’s 18th Wing is tightening approval measures for nighttime exercises after unauthorized training last month involving simulated explosions and gunfire drew complaints from a neighboring Okinawan town.

A unit at Kadena Air Base conducted the exercises “without prior wing-level approval” on the north side of the installation Feb. 25-27, wing spokeswoman Maj. Alli Stormer said in an email Monday.

The training included “personnel recovery, combat search and rescue, and humanitarian assistance and disaster relief in the Indo-Pacific region,” incorporating “controlled sound and visual effects to enhance realism,” she wrote.

“While there was no intent to cause disruption, the wing has implemented stricter approval measures for any nighttime operations,” Stormer said. “We remain committed to being respectful members of the community while continuing to uphold our treaty obligations.”

She declined to provide details on the new approval measures.

Kadena town officials received complaints about explosion or gunshot noises from the base on the night of Feb. 27, a town spokeswoman said Monday. A phone message left on the town’s answering machine and two text messages to an official account on the Line messaging app reported the sounds, she said.

A noise-measuring device recorded explosion-like sounds five times between 8 p.m. and 9 p.m. and six times between 11 p.m. and midnight, the spokeswoman said. The noise levels did not exceed 70 decibels, she said, roughly equivalent to a washing machine or a normal conversation.

The U.S. military typically notifies Kadena town before conducting nighttime exercises, but the town received no prior or post-event communication regarding the training, according to the spokeswoman.

The town contacted the Okinawa Defense Bureau, part of Japan’s Ministry of Defense, on Feb. 28 to confirm the training but had not received a response as of Monday, she said.

“We are currently confirming the facts,” she said. “We will decide our measures after receiving the response.”

Some Japanese government officials speak to the press only on condition of anonymity.