Police in riot gear charged into lingering crowds in Ferguson, Missouri to make arrests as relative calm dissolved in an 11th night of unrest over the shooting of a black teen.
Protests have been punctuated by looting, vandalism and clashes with police every night since Michael Brown, an unarmed 18-year-old, was killed by a white police officer on August 9.
Community leaders, politicians and city officials had redoubled their appeals for order, calling for citizens to stay off the streets after sunset, even though a mandatory curfew had been lifted.
In the hours after darkness fell, protesters were notably fewer in number and more subdued than on previous nights.
Onlookers milled about as civic activists, members of the clergy and even Missouri Attorney General Chris Koster mingled withdemonstrators.
But as the rally was winding down and most of the protesters were leaving the area, someone among the dozens still in the streets hurled a plastic water bottle at police.
Helmeted officers, some with heavy weapons and dogs, suddenly emerged in force and chased down those who resisted as more bottles were thrown. Several were seen being led away in handcuffs.
St Louis County prosecutor's office was expected to begin presenting evidence to a grand jury investigating the shooting today.
The officer who shot Brown, Darren Wilson, has been placed on leave and went into hiding.