Gates to the complex were initially closed, however some were reopened, and movement on streets nearby was restricted. Police cars with flashing lights blocked entrances to Redstone and no traffic was moving on or off of the installation, which also has facilities used by federal law enforcement agencies.
The base has called off a drill on how to respond to an active shooter because personnel learned "everything they need" on Tuesday, Holiday said.
Redstone Arsenal spokesperson Christopher Colster told AL.com that he was not aware of any reported injuries but that the location of the incident has not been determined.
People were gathered outside the Sparkman Center, which includes multiple buildings with offices, an auditorium, cafeteria and an interior courtyard.
David Kumbroch with WHNT tweeted Huntsville Hospital was on heightened alert because of this report, but they've not received any patients.More news: Australia the team to beat at ICC Women's World Cup
More news: Uber CEO could have to take a leave of absence
More news: North Korea denies torturing American detainee Otto Warmbier
Governor Ivey tweeted, "My office is being updated about the situation...and I will continue to closely monitor and pray for a peaceful and quick resolution".
Amy Jay, whose husband was working at the Sparkman Center, said he was told the situation was over through an announcement over the building's public address system. By 11:28am local time officials said checks on the base's childcare center found all children were safely locked inside. "Please watch the news to stay updated". More than 30,000 government employees, civilians and contractors work daily at Redstone.
In the press conference that followed the arrest, Madison County Sheriff Blake Dorning specifically mentioned Redstone Arsenal.
Civilian rocket research was moved to NASA's neighboring Marshall Space Flight Center in 1960.
Redstone has been the center of the Army's missile and rocket programs since the 1950s, when it became the home for the contingent of German rocket scientists who surrendered to American forces at the end of World War II.