St Louis police reported heavy automatic gunfire late on Monday in the area near where Brown was shot and killed on Aug. 9. Police responded with pepper spray and volleys and flash-bang canisters.
Storefront windows were smashed near the Ferguson Police Department, and at least one police cruiser and another vehicle on the street were set on fire. Fire and looting have overtaken several businesses. The Federal Aviation Administration issued temporary flight restrictions for the city.
Protests were also staged in New York, Chicago, Washington, D.C., Seattle and Oakland over a case that has highlighted long-standing racial tensions not just in predominantly black Ferguson but across the United States.
Obama: Accept verdict
Obama said Monday night from the White House that Americans need to accept the grand jury's decision.
"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. He said it was understandable that some Americans would be "deeply disappointed -- even angered," but echoed Brown's parents in calling for any protests to be peaceful.
Attorneys for Ferguson, Missouri, police officer Darren Wilson said in a statement released on Monday that he was following his training and the law when he shot and killed 18-year-old Michael Brown in August.
Reuters and the Associated Press contributed to this report.