The female solder walked into the four-story Combined Arms Support Command Headquarters building at 9 a.m., according to a statement from Fort Lee's media office.
Early reports from officials said the woman turned the weapon on herself and fired one shot.
Officials said the woman, whose identity was not released, was taken to Virginia Commonwealth University Medical Center. Her condition is not known at this time.
Special agents from the U.S. Army Criminal Investigation Command are investigating the incident, which prompted Fort Lee to issue an alert of an "active shooter" situation.
The base was temporarily placed on lockdown before it was lifted a short time later.
A statement posted on Fort Lee's Facebook page said "the law enforcement event is over."
The building where the incident was reported to have taken place is the headquarters of CASCOM, which lists its mission as to "design, develop, and integrate sustainment capabilities into warfighting requirements, foster innovation, and lead change for the future force," according to its website.
The Department of Homeland Security typically uses the term "active shooter" to describe someone actively trying to kill people, usually in a very populated area such as a building or campus.