Members of the community react to speakers during a rally convened in reaction to the shooting of Michael Brown in Ferguson, Missouri August 17, 2014.[Photo/Agencies]

Nixon said that in spite of the clashes, the curfew was a success and the community deserved credit. Speaking on CNN's news show "State of the Union," the governor said he did not know how long the curfew would be in place.

He criticized the Ferguson police department for its decision on Friday to release a video that allegedly showed Brown taking part in a convenience store robbery shortly before the shooting. Police have said the officer who shot Brown had no idea he was a robbery suspect.

"I think it had an incendiary effect," Nixon said on CBS' "Face the Nation." Police "clearly are attempting to besmirch a victim of a shooting," he added.

At Sunday's rally, some participants referred to the theft of a box of cigars as a shoplifting; police had initially called it a strong-arm robbery.

Ferguson Police Chief Tom Jackson defended the release of the surveillance video, over the objections of the US Justice Department. Jackson said he was complying with the news media's requests for information in the case.

The decision to release the video while not giving details of the shooting only fueled outrage. The clashes in Ferguson have pitted mostly black protesters against mostly white police in a residential and retail district.

THREE AUTOPSIES

In calling for the federal autopsy of Brown's body, Holder said it would be conducted in addition to one being conducted by state medical examiners "due to the extraordinary circumstances involved in this case and at the request of the Brown family," Justice Department spokesman Brian Fallon said.

The family is also planning to have a pathologist conduct an independent examination of the body, a family spokesman said.

President Barack Obama received regular briefings on the situation in Ferguson while on vacation in Martha's Vineyard, including from senior adviser Valerie Jarrett.

The US Department of Justice and the St. Louis County Police department are investigating Brown's death, which has been described differently by the police and by a friend who was walking with him at the time.

Police say that after Wilson asked Brown to move out of the road onto a sidewalk, Brown reached into the patrol car and struggled with Wilson for the officer's service gun. Wilson, who sustained a facial injury, then shot Brown a number of times.

The friend, Dorian Johnson, 22, and at least one other witness have said the officer reached out through his car window to grab at Brown and the teenager was trying to get away from the officer when he was shot. Brown held up his hands in a sign of surrender, but the officer got out of his patrol car and shot Brown several times, they said.