US Osan Air Base in South Korea in lockdown, as precaution over reports of shooter on site

SEOUL (AFP) - The United States Osan Air Force base in South Korea was under lockdown on Monday after reports of an active shooter on the site, the 51st Fighter Wing based there said.

“We have received reports of a possible active shooter incident. A perimeter has been established and security forces are sweeping the area,” the fighter wing said in a statement posted on its official Facebook page at 11.20am local time.

Osan's 51st Fighter Wing posted on its official Facebook site that security forces had swept half of all three buildings in the area but had no reports yet of suspicious activity.

A statement from the principal of the school Morgan Nugent suggested the lockdown had been a precautionary reaction to a possible hoax call.

“One of our teachers received a call that sounded automated saying that there was an active shooter drill taking place,” he said.

“There was no scheduled school shooter drill on base, so we have decided to err on the side of safety and went into a full school lockdown,” he said.

“Once we are given an all clear we will go ahead and continue the school day,” he added.

US military spokesman Stacy Foster said people on the base had been told to stay in their quarters until further notice, according to the Associated Press.

The 51st Fighter Wing said the lock down had been extended to the entire base, and added that a complete security sweep would be conducted before signalling the all-clear.

"Here are the facts as we know it right now. One of our teachers received a call that sounded automated saying that there was an active shooter drill taking place. He reported this to me immediately," a post on Osan's 51st Fighter Wing's Facebook page said.

"There was no scheduled school shooter drill on base so we have decided to error (sic) on the side of safety and went into a full school lockdown.

"Security Forces have responded to the school and are doing a sweep of the whole school and its perimeter. Once we are given an all clear we will go ahead and continue the school day as is with a chance for a debrief to our kids at the end of the school day."

Spokesman Brandon Baccam said officials were still trying to get information and details were not available as of 11.20am, according to the Stars And Stripes website.

Security forces were seen at about 11.15am at the base’s middle school and high school, said Stars and Stripes, adding that a loudspeaker was repeating this message in English and Korean: “Lockdown, lockdown, lockdown. Seek safety and shelter.”

The 51st Security Forces Squadron had a drill for a live shooting situation last month. It used the Osan Middle School as the setting, according to the Wing's website.

Osan Air Base, some 104.6km south of Seoul, is one of a number of facilities housing the 28,500 US military personnel permanently based in South Korea as a deterrent to North Korea, whose 1950 attack started the Korean War.