Residents of a St Louis suburb are awaiting a grand jury's decision on whether to bring criminal charges against a white policeman who fatally shot a black teenager.
The killing of 18-year-old Michael Brown by officer Darren Wilson in Ferguson, Missouri on 9 August prompted weeks of demonstrations by protesters demanding Mr Wilson be indicted.
The policeman said he fired on the teenager in self-defence, while Mr Brown's companion has said the young man had his hands raised at the time in an act of surrender.
Activists and police have been taking steps to avoid more turmoil, especially if the grand jury does not indict Mr Wilson.
Media reports suggesting the verdict could be imminent have increased tensions in the area in recent days, fuelled by nightly rallies and increasingly high-profile law enforcement presence.
Steady rain put a bit of a dampener on most of last night's protests.
About 40 mostly teenage demonstrators strode up and down a main street in Ferguson, waving upside-down US flags and home-made placards and chanting, "We're young, we're strong, we're marching all night long".
Other protesters gathered outside Ferguson police headquarters for a fourth straight night, while convoys of law enforcement vehicles patrolled after dark.
Mr Brown's mother, Lesley McSpadden, earlier told demonstrators gathered at the site where her son's body had lain that they must remain peaceful whatever the grand jury decides, and that they should not be provoked by the police.
