Following the on-scene investigation, the Oklahoma City Police Department said that the incident was a result of an argument between two people. A person was shot in chest and the suspect was on the loose, police said, adding that the incident was isolated.
Local media said earlier that the mall was evacuated, while officers "armed with rifles" secured the adjacent and parking areas of the mall.
Oklahoma's KFOR broadcaster said, citing eyewitnesses, that after the first reports of the shooting emerged, people inside the mall panicked and stampeded toward the exits.
The Oklahoma City Police Department said earlier that at least one person was injured by gunfire.