Police say that violence that erupted in a U.S. city after a grand jury's decision not to indict a white police officer in the shooting death of an unarmed black teenager was the "worst" since August, when the unrest started.
Meanwhile, attorneys for the family of Michael Brown criticized the grand jury process that led to a decision not to indict Darren Wilson, the white police officer who shot and killed the black teenager in August.
The August 9 shooting of Michael Brown by police officer Darren Wilson sparked weeks of sometimes violent protests in Ferguson, Missouri, as several witnesses said they saw Wilson shoot Brown after he had turned to face the officer with his hands up.
But Prosecuting Attorney Bob McCulloch said the grand jury on November 24 "determined that no probable cause exists to file any charge against officer Wilson."
He said the grand jury of nine whites and three blacks heard testimony from 60 witnesses about what happened during the incident that led to Brown's death, and that much of it was inconsistent with the physical evidence.
Wilson could have faced charges ranging from involuntary manslaughter to first-degree murder.
The announcement sparked a fresh wave of riots, with police cars and at least a dozen buildings set alight, shops looted, and gunfire resounding in the city.
Police in armored vehicles used tear gas and smoke canisters to disperse the crowds, and U.S. aviation authorities issued temporary flight restrictions.
Police say 61 people were arrested.
Ferguson is a mostly black suburb of St. Louis that has a predominantly white power structure.
St. Louis County Police Chief Jon Belmar said the violence was "probably much worse than the worst night" of protests in August.
On November 25, Brown family lawyers Benjamin Crump and Anthony Gray said the process had been unfair because the prosecutor on the case had a conflict of interest and because white police officer Darren Wilson was not cross-examined.
They said a special prosecutor should have been appointed.
At the same news conference, civil rights activist Reverend Al Sharpton criticized the process that led to the grand jury ruling.
Sharpton also criticized those who committed violence Monday night, saying they were not on the side of Michael Brown.
On November 24, peaceful protests were held after the ruling in cities such as New York, Washington, Chicago, Seattle, Oakland, and Los Angeles, in a case that has highlighted racial tension in the United States.
President Barack Obama had called for protesters to remain peaceful and for police to show restraint.
Addressing the nation from the White House, Obama said, "We are a nation built on the rule of law, so we need to accept that this decision was the grand jury's to make."
Obama said it was "understandable" that many Americans were "deeply disappointed, even angered" but he urged that any protests over the decision be peaceful.
The fresh riots in Ferguson come amid renewed racial tensions fueled by what members of minorities say is unnecessarily violent police behavior.
On November 22, Cleveland police shot 12-year-old Tamir Rice dead after the boy had waved a fake gun at a playground. Rice died later in hospital.
With reporting by AP, Reuters, and dpa