Active shooter reported at Air Force base in Ohio

The active-shooter threat Thursday at Wright-Patterson Air Force base in Ohio turned out to be just someone who didn’t know about a scheduled drill.

Earlier in the afternoon, federal and state authorities in armored vehicles and unmarked cars had swarmed onto the sprawling Air Force base, the base was placed on lockdown, and workers told to shelter in place.

But on its Twitter feed, the base later said there had never been a threat to the Wright-Patt Medical Center.

“There was no real world active shooter incident on Wright-Patterson AFB and base personnel remain safe,” the official base account wrote.

In a statement posted by its feed, the base explained what had happened.

About 12:40 p.m. local time, “an unknown individual called 911 believing that there was a real-world incident occurring within the base hospital. As a result, security forces responded to the scene,” the base wrote.

However “this reported incident occurred during a normal, scheduled installation exercise which included an Active Shooter scenario at a separate location.”

“Upon investigation, it was determined that the incident … was not an actual Active Shooter incident,” Wright-Patterson officials wrote.

One shot was fired by security forces, the base said, to open a locked door.

The base is Ohio’s largest single-site employer with more than 27,000 civilian employees and military personnel.

• This article was based in part on wire service reports.