(CNN)The US Army's Redstone Arsenal post in Huntsville, Alabama, is on lockdown because of a "possible active shooter," the facility's Twitter account said Tuesday.
There were reports of a shooter at Building 5301 -- the Aviation and Missile Command building -- at the post's Sparkman Center, Army spokeswoman Kim Hanson said.
"Installation is locked down. Run hide fight," the post's Twitter account said.
An Army email sent to facility personnel and relatives was more explicit, saying an active shooter was on Building 5301's second floor.
"If you are not in the Sparkman Center, stay away from the area," said the email, sent at 10:08 a.m. CT and obtained by CNN.
Redstone Arsenal on lockdown for 'possible active shooter' - CNN.com