“Three servicemen sustained lethal injuries as a result of the attack,” Russia’s Western Military District said in a statement carried by Interfax.
“The command of the military unit, acting together with law enforcement agencies, is working to track down and detain the assailant,” it added.
The statement said the attack began in the early hours of Monday.
An unnamed Interfax source said the shooting was sparked when an altercation broke out between the soldier and an officer during an inspection.
The soldier “grabbed a handgun” from the officer’s holster and fired, the source said, with three colleagues reported dead.
Authorities on the military base were negotiating with the suspect who had locked himself in a building, Interfax reported.