Wright-Patterson Air Force Base was placed on lockdown Thursday afternoon for several hours after a 911 call about an active shooter on base.

It turns out the caller confused an active shooter drill with a real attack on the base, according to base officials.

Updated 5:30 p.m. EDT Aug. 2: Officials at Wright-Patterson Air Force Base said a 911 call Thursday during base exercises prompted an active shooter report at the base hospital.

The training exercise was taking place about half a mile away from the hospital and did not include the use of any simulated gunfire, base spokesperson Daryl Mayer said.

The weapons that were used were brightly colored and clearly not real, Mayer said.

It’s unclear what was reported in the 911 call, but once the call was received, the exercise was paused and the base responded to what it thought was an active threat, Col. Tom Sherman, installation commander for the 88th Air Base Wing, said.

The active shooter was reported around 12:40 p.m. At 1:18 p.m., the base tweeted there was a report of an active shooter, and at 3:37 p.m. the base tweeted there was not an active threat.

The hospital facility is approximately 99,000 square feet. It took a systematic amount of time to clear the facility, Sherman said.

“We don’t believe anything went wrong in this case” he said. “I’d like to redefine it by saying we received a 911 telephone call from inside the hospital from someone who truly believed there was an emergency situation taking place.”

One shot was fired by a security forces member who was attempting to open a locked door during a sweep of the facility, according to officials.

An investigation is ongoing.

Sherman said it’s unknown at this point if anyone will face consequences, pending the investigation.

Update 4:45 p.m. EDT Aug. 2: "Everyone is safe," Col. Tom Sherman, installation commander, 88th Air Base Wing, said at an afternoon press conference on reports earlier Thursday of an active shooter on base at Wright-Patterson.

The incident at the medical facility was not an actual active shooter incident.

The scene has been cleared safe, and all personnel have been advised to stay clear of the hospital at this time.

Sherman said he is limited in what he can say because the investigation is ongoing.

“Our base personnel are trained to handle these situations. They responded with an incredible amount of professionalism,” Sherman said.

“Our hospital facility is approximately 99,000 square feet. It took a lengthy amount of time to clear the facility,” he said.

“We don’t believe anything went wrong.”

“We received a 911 telephone call from inside the hospital from someone who truly believed there was an active shooter situation,” Sherman said.

Sherman said when a real world event takes place, the exercise ceases to exist and the real world incident will be dealt with.

He said it’s unknown at this point if anyone will face consequences, pending the investigation.

Update 3:45 p.m. EDT Aug. 2: Officials said Thursday's police response was prompted by a person who called 911 thinking that an active shooter drill on base was a real attack.

Update 3:15 p.m. EDT Aug. 2: Elena Arrasmith, who works on base, told WHIO that she was on break from training exercises and found the base on lockdown when she came back.

“We were just in our exercise,” Arrasmith said. “I left for lunch and came back to a real world event happening.”

Arrasmith, who works as an administrator on base, said she hadn’t experienced anything similar to this in her time on the base.  She was waiting outside the base at around 2:40 p.m. to pick up her daughter, who was on base.

“I just want to go and get her, and I can’t,” she said. “I don’t think I’ve experienced anything ... worse than that.”

Update 2:40 p.m. EDT Aug. 2: Wright-Patterson Air Force Base has given an all-clear to base personnel advising that the threat has passed, according to an alert. However, people are still being asked to stay clear of the medical center on base.

Update 2:25 p.m. EDT Aug. 2: Emergency dispatch traffic suggests someone might be barricaded inside the hospital. People are being escorted from the building, with their hands up, by people wearing camouflage uniforms.

Law enforcement officials have given multiple accounts of Thursday’s incident. Base officials have not confirmed a shooting took place.

Cassie Barlow, the former 88th air base wing commander, called news of the shooting "disturbing,” but he said individuals on base have the training they need to respond to an active shooter.

"There's so many trained individuals at Wright Patterson who know exactly what to do because they've walked through this exact scenario," Barlow told WHIO.

Barlow said there was never an active shooter during her time as commander, but there were drills.

Update 2 p.m. EDT Aug. 2: Officials with the Bureau of Alcohol, Tobacco, Firearms and Explosives are responding to reports of a shooting at Wright-Patterson Air Force Base.

Update 1:55 p.m. EDT Aug. 2: The base was scheduled to hold quarterly base-wide exercises from July 30 to August 3. It's unclear whether the exercises played a role in the incident reported Thursday.

The military medical center on base has more than 4,000 annual admissions, according to its license.

Update 1:40 p.m. EDT Aug. 2: Officials with nearby Wright State University said in a tweet Thursday afternoon that they were told the incident was contained by 1:35 p.m.

Police did not immediately confirm the situation was contained.

Original report: Authorities are investigating reports of a shooting at the hospital at Wright-Patterson Air Force Base, officials said in an alert sent to base personnel.

"Emergency responders are enroute," the alert said. "All WPAFB Gates are Closed. All personnel take cover. Limit all communication to emergency use only."

Marie Vanover, director of public affairs at WPAFB, said authorities were called around 12:40 p.m. after an unspecified incident occurred in building 830, the base's hospital.

“No additional details are available at this time and info will be released as it becomes available,” she said.

Check back for updates to this developing story.