Officials said an anonymous caller first reported shots fired just before 9 a.m. Personnel were required to shelter in place until after authorities responded.
The lockdown was lifted around 12:20 p.m., with the combat center saying that a weapon was "inadvertently discharged." Officials add that no one was hurt.
No other details were immediately available.
The combat center, which was used for flight training during World War II, is home to one of the largest military training areas in the country.