(Adds retirement of police officer suspended pending a review for a speech in 2012 and Ohio protest)
Aug 30 (Reuters) - Hundreds of marchers took to the streets in Ferguson, Missouri, on Saturday, local media reported, with protesters calling for justice three weeks after a white police officer shot and killed Michael Brown, an unarmed black teenager.
Ferguson police officer Darren Wilson shot the 18-year-old Brown on Aug. 9. The shooting sparked violent protests in the St. Louis suburb and drew global attention to race relations in the United States.
For days after the shooting, police and demonstrators in Ferguson clashed nightly, with authorities criticized for mass arrests and the use of military gear, which some observers described as heavy-handed tactics.
Organizers on their Facebook page said the march on Saturday was held to protest police killings, brutality, profiling and cover-ups.
Marchers began gathering in a restaurant parking lot before walking to the spot where Brown was shot, the St. Louis Post-Dispatch reported.
"I came here because I want to be a part of the spirit of the movement," Memphis resident Ian Buchanan, 44, told the newspaper.
Authorities have released few details about the shooting. A St. Louis County grand jury has begun hearing evidence and the U.S. Justice Department has opened its own investigation.
In differing accounts, police have said Brown struggled with Wilson, who shot and killed him. But some witnesses say Brown held up his hands and was surrendering when he was shot multiple times in the head and chest.
The Post-Dispatch also reported on Saturday that a St. Louis County police officer who took part in policing the protests, Dan Page, has retired after 35 years on the force, several days after he was suspended when his department said it would launch a review of a 2012 speech that Page made to the group Oath Keepers in which he made pointed remarks about President Barack Obama, the U.S. Supreme Court and Muslims, among others.
In a video of the speech posted online, Page, an Army veteran, said that he had killed in the past and would kill again if necessary.
Oath Keepers describes itself as a non-partisan group devoted to defending the Constitution and says its members pledge to not obey unconstitutional orders.
The Southern Poverty Law Center, a civil rights group, tracks the group on its Hatewatch blog.
A spokesman for St. Louis County Police did not immediately return a call and email for comment on Saturday.
Meanwhile, The Dayton Daily News reported several hundred people showed up in a rally outside of a Walmart in Beavercreek, Ohio, on Saturday to urge release of a surveillance video from early this month of police shooting John Crawford III, who was holding a BB gun inside the store. (Reporting by Brendan O'Brien in Milwaukee and Kevin Murphy in Kansas City.; Editing by Alex Dobuzinskis and Leslie Adler)