It is home to Army missile defence programs and other military offices. He said initial 911 reports like this can often be confused and was in this case.
"What I really want to make clear when it comes to the safety of our work force, our systems worked", Holliday said.
The alert initially caused some confusion, according to local media, because an active shooter drill had been planned to take place tomorrow.More news: Syrian Observatory: air strike kills 42 in Islamic State-held town
He explained they coordinate with Huntsville police, the Redstone Arsenal's own police, the FBI and more federal authorities. "Honestly, if we have to overreact, I would rather overreact than underreact".
In the Twitter announcement of the possible shooter, Redstone Arsenal also told all those on campus to "Run hide fight".
"I believe we saw very clearly that the actions of our first-responders was spot-on", Holliday said. Authorities are asking people to avoid the area.
"You have to understand the size of that building", he told reporters hours after the lockdown had been lifted. Jay wrote in a message to The Associated Press.More news: India's largest container port hit by global cyber attack
Nasa's Marshall Space Flight Centre, which oversees rocket propulsion operations, is also located at Redstone.
Officials are allowing traffic onto and off the base, post spokesman Chris Colster said.
Alabama Governor Kay Ivey said in a tweet her office is being updated about the situation. Robert Aderholt and Mo Brooks were monitoring the situation and Ivy said she would "pray for a peaceful and quick resolution", Fox News reported.
Limestone County sheriff's spokesman Stephen Young said the reaction to the situation at Browns Ferry was likely "an abundance of caution-type thing based on what's going on elsewhere", referring to the arsenal.More news: McConnell on Trump Healthcare Meeting: 'We Made Good Progress'
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