Personnel expressed confusion on the authenticity of the emergency message
A "mass casualty exercise" in Okinawa, Japan, became more real than expected on Thursday after a vehicular accident threatened the lives of more than eight U.S. Marines.
A Light Tactical Vehicle in the Okinawan Jungle Warfare Training Center rolled onto its side Thursday with multiple military personnel aboard.
"There will be an investigation on this afterwards," 3rd Marine Division spokesman Maj. Clay Groover said to outlet Stars and Stripes in a Thursday statement. "Everyone seems to be OK at this point."
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Photo published to social media shows a support team training exercise conducted by the 3rd Marine Littoral Regiment with the 25th Combat Aviation Brigade at Marine Corps Training Area in Bellows, Hawaii. (3dmardiv/Instagram)
No life-threatening casualties were reported, but those involved suffered some injuries.
Marines sustained potential concussion, Groover told Stars and Stripes, as well as back pain and reports of dizziness.
The accident coincided with a pre-planned emergency preparedness drill at U.S. Naval Hospital Okinawa.
"USNHO is currently experiencing a real world mass casualty event," the hospital announced at 1 p.m. "Please avoid the Emergency Department for non-emergent needs."
The hospital emphasized that the announcement was a "Real World Actual" incident and not part of the scheduled drills. It announced the situation via social media.
The U.S. Naval Hospital Okinawa, which issued an emergency message to personnel on the same day a "mass casualty exercise" was expected, leading to widespread confusion. (Google Earth)
Public comments expressed confusion due to the coincidence of the drills and the actual rolled vehicle incident.
The hospital was forced to continue expressing the authenticity of the warning, telling the public, "This is not an exercise."
"We are currently experiencing a real-world emergency involving multiple patients," the hospital wrote at approximately 2:10 p.m.
Between eight and 10 Marines were aboard the vehicle when it lost control and rolled onto its side, according to Stars and Stripes.
The incident occurred in the island's northern region.
Timothy Nerozzi is a writer for Fox News Digital. You can follow him on Twitter @timothynerozzi and can email him at