The famous Fort Knox compound in Kentucky was put on lockdown at around 6:30 p.m. Tulsa time, because of a shooting.
Officials say the shooting happened somewhere near the Humans Resources Command of the army post, which has around 3,800 employees.
There was no immediate word about whether anyone was hurt or killed.
Fort Knox public affairs officer Ryan Brus told Fox News they had boosted security for anyone coming into or leaving from the base.
WDRB.com reported the lockdown had ended around 7:00 p.m. but that was unconfirmed.