The airbase earlier tweeted: 'Emergency responders are enroute. All gates are closed. All personnel take cover. Limit all communication to emergency use only'
A TRAINING drill involving an "active shooter scenario" sparked a full scale alert at a US military base - involving armed cops and the FBI.
Wright-Patterson Air Force Base in Ohio was put on total lockdown earlier this evening amid emergency reports of a gunman on the loose.
The airbase sparked the alarm when it tweeted: "All gates are closed. All personnel take cover. Limit all communication to emergency use only."
However, officials have now revealed the drama was sparked when someone dialled 911 fearing there was a real shooter on the loose inside the compound.
They say the training exercise did not use any simulated gunfire and the weapons being used were brightly coloured and clearly not real.
Colonel Tom Sherman, installation commander, 88th Air Base Wing said: "We don’t believe anything went wrong in this case.
“I’d like to redefine it by saying we received a 911 telephone call from inside the hospital (on the base) from someone who truly believed there was an emergency situation taking place.”
An investigation has now been launched to determine exactly what happened and the military has confirmed it has counsellors working with those upset by the misunderstanding.
The base tweeted the incident occurred during a normal, scheduled installation exercise which included an active shooter scenario at separate location.
The base said in its statement that an unknown individual called 911 "believing there was a real world incident occurring within the base hospital."
The statement said security forces responded to the scene and began clearing the facility.
"In an attempt to breech a door that was locked, a security forces member discharged his firearm to open the door and continue the sweep of the facility," it said.
"The scene has been declared safe and all personnel have been advised to avoid the base hospital area for the time being."
The original statement, which called for a lockdown, did not elaborate on the nature of the emergency, except to say that they were responding to a "reported Active Shooter incident."
The base's original alert said all gates were closed.
"All personnel take cover," the alert said. "Limit all communication to emergency use only.";
Unconfirmed reports from the scene earlier suggested a gunman has barricaded himself inside the giant base's medical wing.
Neighbouring Wright State University and nearby schools also went into lockdown after the first alerts went made.
Approximately 20 minutes after the alert was issued, the university tweeted that they had been told the incident had been “contained.”
Ohio Senator Sherrod Brown issued a statement on Twitter after the reports, asking for prayers from the community.
“People join us in keeping the first responders, Wright-Patt personnel and the entire Dayton community in our thoughts as we pray for the safety of everyone involved,” he wrote.
Wright-Patterson Air Force Base in southwest Ohio, has 27,000 military, civilian and contractor employees, according to the base's U.S. Air Force website.
The base is headquarters for the Air Force's worldwide logistics system. The base performs a "world-class laboratory research function," according to the website.
The base is the size of a medium-sized city. There are shopping centers, child care centers and housing and the "large medical center" on base, according to the website.
