Updated 2:02PM EST
A lockdown has been lifted at an Alabama military installation, though officials say they are still investigating a possible active shooter incident there.
Christopher Colster, a spokesman for Redstone Arsenal in Hunstville, said Tuesday that officials do not believe there is an ongoing threat. No injuries or arrests have been reported.
Colster says a training exercise was ongoing that was supposed to end Wednesday. Officials had said on Facebook that an active shooter training exercise was planned for this week. But Colster would not say whether the active shooter report was part of that exercise, adding: "I really can't say at this point what happened. I'm not sure myself."
HUNTSVILLE, Ala. — A north Alabama military post said in a tweet it was on lockdown Tuesday amid reports of possible active shooter, telling workers to "run hide fight."
Redstone Arsenal received reports of a person possibly armed with a weapon at a building on the base, spokesman Christopher Colster told WAFF-TV in a live broadcast.
Colster said there were no confirmed casualties, and officials hoped workers could return to normal activities within a couple of hours.
A safety drill was planned for Wednesday, but Colster said the report of a shooter was not part of any exercise.
Television stations in the area are quoting Huntsville Hospital officials as saying they've heard of no incoming patients
More than 30,000 government employees, civilians and contractors work daily at Redstone, which adjoins the city of Huntsville. It is home to Army missile defense programs and other military offices.
Check later for updates.