A torii, a traditional Japanese gate most commonly found at a Shinto shrine, is pictured at Camp Zama, Japan, Sept. 22, 2022. (Akifumi Ishikawa/Stars and Stripes)

TOKYO — An investigation was underway Friday morning after an “unusual email” was sent to officials at U.S. Army Garrison Japan, according to an Army spokeswoman.

Some soldiers at Camp Zama — home of the garrison and U.S. Army Japan just outside the Japanese capital — reported receiving text messages and phone calls from their supervisors around 8:30 a.m. about a bomb threat.

They said they were asked to refrain from reporting to work until given the all-clear, which came about a half-hour later.

“Out of an abundance of caution, U.S. Army Garrison Japan officials are currently working with Japanese officials to investigate the message,” garrison spokeswoman Amanda Kurka told Stars and Stripes in an email Friday.

No alerts or messages about the email or a bomb threat were reported on the garrison’s social media accounts Friday.

“U.S. Army Garrison Japan officials will provide community updates as needed,” Kurka wrote in her message.

The incident comes about two weeks after a bomb threat at Yokota Air Base in western Tokyo emptied the 374th Airlift Wing’s headquarters and several other buildings, including the base exchange, enlisted club and some residences, for about two hours on June 15.

The evacuations came after a Japanese comment, translating to “I planted a time bomb,” was posted on Yokota’s official Facebook page. The comment has since been removed.

No injuries were reported from the incident, which remains under investigation, wing spokesman 1st Lt. Danny Rangel told Stars and Stripes in a text message Friday.