Nine American police officers have violently arrested an unarmed black teenager in California for jaywalking.

A video of the incident posted to YouTube shows a police officer hitting the 16-year-old African American with his baton before several other officers get involved.

The altercation happened in the city of Stockton on Wednesday morning after the teenager was caught walking in a bus-only lane.

One of the officers strikes the boy in the face and orders him to the ground but the teen does not comply.

An unseen female bystander is heard shouting at police in an effort to stop the scuffle. “That’s a kid! Don’t touch him, leave him alone! That’s a kid. Are you serious? He didn’t do nothing (sic) wrong.”

Several patrol cars arrive and four officers knock the boy to the ground, handcuff him and take him to a car.

The bystander raises her voice again in protest. “That is a child! That is a child that was jaywalking! What’s wrong with y’all?”

Similar cases of excessive use of force by Stockton police have been reported in recent years.

At the height of the Black Lives Matter protests early this year, police brutality involving the shooting deaths of at least three unarmed black and Hispanic men was the subject of demonstrations in the city.