A Baltimore police officer shot and wounded a 13-year-old boy on Wednesday after he refused to drop a replica of a semiautomatic pistol, the city's top law enforcement official said. The boy is expected to survive.

The shooting occurred on the one-year anniversary of riots that broke out in Baltimore after the funeral of Freddie Gray, who died after sustaining neck injuries in a police van.

Two officers were patrolling in West Baltimore about 4 p.m. when they saw the teen with the replica handgun, Commissioner Kevin Davis said from the scene.

The officers identified themselves and the teenager took off running, Davis said. The officers chased the teen for about 150 yards before catching up with him and ordering him to drop the gun, the commissioner said.

The boy did not drop the gun, Davis said, and one officer shot him in the leg. The youth was taken to a hospital with non-life-threatening injuries, authorities said.

No one else was hurt and a replica handgun was recovered.

Davis said he looked at the replica afterward and couldn't tell it wasn't a real gun.

"The officers had no way of knowing it was not a firearm," Davis said. "I have no reason to believe the officers acted inappropriately."

After the shooting, the youth's mother approached officers and said she knew her son had left their home with what she described as a BB gun, Davis said.

"Why did a 13-year-old have a replica pistol in his hand?" Davis said. "I don't know why he chose to run, why he didn't drop the gun."