Police officer shoots and kills black teenager in Wisconsin

A police officer shot and killed an unarmed 19-year-old black youth who allegedly assaulted him in Madison, in the US state of Wisconsin, the city's police chief said.

The incident on Friday evening touched off protests in the Midwestern university city, and local media reported a heavy police presence in the area where the shooting occurred.

It was the latest in a string of police shootings of young blacks that have set racial tensions on edge in the United States, igniting a nationwide debate over police tactics in minority communities.

Police chief Mike Koval told WKOW television the police officer was responding to a report of a battery and had forced his way into an apartment after hearing sounds of a disturbance inside.

"Once inside the home, the subject involved in the incident - the same one who had been allegedly out in traffic and had battered someone - this same subject then assaulted my officer, and in the context of mutual combat in that sense, the officer did draw his revolver and subsequently shot the subject," Koval said.

Koval said the youth died in hospital. An initial search found no gun or weapon at the scene.