WASHINGTON (AFP) - A US police officer from Milwaukee, Wisconsin who shot and killed an African-American man in a park last April will not be charged, prosecutors said on Monday.

The incident - in which Dontre Hamilton, 31, was shot 14 times - prompted demonstrations that foreshadowed the August shooting of unarmed teenage Michael Brown in Ferguson, Missouri.

Milwaukee police officer Christopher Manney was responding to a call from coffee shop employees complaining about Hamilton, who appeared to be homeless, sleeping in a nearby park.

According to Manney, who has since been dismissed from the force, a scuffle broke out as he was frisking Hamilton and he lost control of his baton, prompting him to draw his sidearm and shoot.

"This was a tragic incident for the Hamilton family and for the community," said prosecutor John Chisholm.

"But, based on all the evidence and analysis presented in this report, I come to the conclusion that Officer Manney's use of force in this incident was justified self-defence and that defence cannot be reasonably overcome to establish a basis to charge Officer Manney with a crime."

Hamilton family lawyer Jonathan Safran is to seek a federal investigation into the shooting, the Journal Sentinel newspaper in Milwaukee reported.

Manney is the latest in a series of white police officers who have avoided prosecution after incidents in which African-American men have died.

Brown was shot and killed in broad daylight in the St Louis suburb of Ferguson on August 9, prompting nationwide protests and renewed debate about race relations and law enforcement.

A grand jury reviewed the case for weeks before deciding not to indict the officer involved, Darren Wilson.

A grand jury in New York similarly cleared a police officer who allegedly strangled Eric Garner with a chokehold. The 43-year-old African-American was suspected of peddling untaxed cigarettes.