ST. CHARLES, Mo. (AP) -- St. Charles police say an officer who shot and killed an armed robbery suspect was acting in self-defense.

The name of the officer and the suspect have not been released. The officer is a 15-year veteran of the department and is on administrative leave pending an internal investigation. But police say preliminary indications are the officer did nothing improper.

The incident happened early Wednesday after police responded to an armed robbery at a convenience store. The suspect drove away, prompting a pursuit.

Police say the suspect got out of the car, tried to enter a home, then tried to flee. When confronted by police, he allegedly threatened officers with a handgun and was shot. He was taken to a hospital, where he was pronounced dead.