Police in the US town of Ferguson, Missouri, have made a number of arrests after demonstrators blocked a road and threw rocks at officers.
The protests came a day after the first anniversary of the fatal shooting of unarmed black teenager Michael Brown.
A state of emergency was declared after another black teenager was shot by police in scuffles on Sunday night.
Authorities said the teen, Tyrone Harris, was wounded during a gun battle with plainclothes officers on the anniversary of Michael Brown Jr's death.
The 18-year-old allegedly opened fire on the officers, who had been tracking Harris in an unmarked van on Sunday night.
St Louis County prosecutors have charged Harris with four counts of assault on law enforcement and shooting at a motor vehicle.
The teen, who remains in critical condition in hospital, was ordered held on US$250,000 (€226,913) bond.
Brian Fletcher is a former Mayor of Ferguson.
Colin Jeffrey is the news director at KTRS in St Louis. He told Newstalk Breakfast the situation had been peaceful across the weekend, up until Sunday.
