Tear gas filled the streets of Ferguson, Missouri after the fourth successive night of protests at the shooting of an unarmed black teenager by police.
The latest series of confrontations saw two journalists, one from the Washington Post and another from the Huffington Post arrested.
Demonstrators defied police to gather again to protest at the shooting of 18-year-old Michael Brown in the suburb of St Louis on Saturday.
Police had pleaded with residents to stay at home after days of looting. Already one convenience store has been burned out and other businesses damaged in the violence.
Armed with assault rifles and bolstered with armoured personnel carriers, police staged a show of force in an attempt to keep control of the streets.
But it was to no avail as the anger among protesters showed no sign of abating, especially with the authorities still refusing to release the name of the officer who shot Mr Brown.
Police fired pepper spray and tear gas in an attempt to disperse the crowd as protesters showed no sign of being willing to move.
The protesters had been told to leave the area completely or face arrest. Police told the demonstrators that their peaceful assembly was "no longer peaceful".
Last night's angry protests reflected the mounting tension in Ferguson, where 67pc of the population is black, but all but three of the town's 53 police officers are white.
Figures released last year by Missouri's Attorney General showed that seven times more black drivers were stopped by police than white.
The two journalists, Ryan Reilly of the Huffington Post and Wesley Lowery of the Washington Post, were arrested in a branch of McDonald's where they had been working.
Mr Reilly, of the Huffington Post, said he was apprehended after he snatched a photograph of a member of a police SWAT team who had asked him to show identification.
"The officer in question, who I repeatedly later asked for his name, grabbed my things and shoved them into my bag," said Mr Reilly said. "He used his finger to put a pressure point on my neck.
"They essentially acted as a military force. It was incredible," he added. "The worst part was he slammed my head against the glass purposefully on the way out of McDonald's and then sarcastically apologised for it."
Both men were later released, with Thomas Jackson, the Ferguson police chief, attributing the arrest to an officer "who didn't know better".
Police in riot gear fired tear gas into a crowd of protesters, as tensions rose even amid calls for collective calm.
Authorities have been vague about what led the officer to open fire on the unarmed teenager, saying only that the shooting was preceded by a scuffle of some kind with a man in which the officer's weapon discharged once inside a patrol car.
Some civil rights leaders have drawn comparisons between Brown's death and that of 17-year-old Trayvon Martin, who was fatally shot by a Florida neighborhood watch volunteer, who was later acquitted of murder charges.
National NAACP President Cornell William Brooks implored residents to "turn your anger into action" while condemning the violent response to Brown's death.
"To sneak around under the cover of darkness, to steal, to loot, to burn down your neighbourhood - this does not require courage," he said. "Courage is when you strive for justice," he said.
The FBI has opened an investigation into Brown's death, looking into possible civil rights violations. Witnesses have said that Brown had his hands raised when the unidentified officer approached with his weapon drawn and fired repeatedly.
Brown's parents have been among those calling for calm.