US President Barack Obama said there is "no excuse" for excessive force by police or those looting and carrying guns in the Missouri town where a teenager was shot by an officer.
He said: "There is no excuse for excessive force by police or any action that denies people the right to protest peacefully. Ours is a nation of laws for the people who live under them and the people who live under them."
He added: "We have all seen images of protesters and law enforcement in the streets. It is clear that the majority are peacefully protesting. It is also clear that a minority are not."
While he accepted that the shooting had raised passions across much of the community he said: "Giving into that anger by looting or carrying guns or even attacking the police, only serves to raise tensions and stir chaos. It undermines rather than advancing justice."
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It comes as households already face a triple-whammy from airfares, fuel and electricity prices.