A demonstrator celebrates as a business burns during rioting following the grand jury decision in Ferguson, Missouri on Monday. The jury declined to indict officer Darren Wilson for shooting dead black teenager Michael Brown. Photo: AFP

The St Louis area was braced for another day of protests on Tuesday after a grand jury cleared a white police officer in the fatal August shooting of an unarmed black teenager, sparking a night of violent and racially charged rioting.

About a dozen buildings in Ferguson, Missouri, burned overnight and police fired tear gas and flash-bang canisters at protesters, said St Louis County Police Chief Jon Belmar. Sixty-one people were also arrested, police added.

Although no serious injuries were reported, Belmar said the rioting on Monday night and early Tuesday morning was "much worse" than disturbances which erupted in the immediate aftermath of the shooting of 18-year-old Michael Brown by police officer Darren Wilson on August 9.

Protests were also staged on Monday in New York, Chicago, Seattle, Los Angeles, Oakland and Washington, DC, over a case that has highlighted long-standing racial tensions not just in predominantly black Ferguson but across the US.

Schools in Ferguson and its surrounding cities said they would remain closed on Tuesday. Protesters planned to demonstrate on Tuesday outside the courthouse in Clayton, Missouri, where the grand jury sat.

The rioting came despite calls for calm from officials ranging from Missouri Governor Jay Nixon to President Barack Obama. Activist leaders had spent weeks training protesters in nonviolent civil disobedience techniques and police had also been through conflict de-escalation training, though tempers flared after crowds threw bricks at police and set patrol cars on fire following the grand jury's decision.

St Louis police reported heavy gunfire late on Monday in the area near where Brown was slain, but Belmar said officers did not fire a shot, even after they were pelted with rocks, bottles, batteries and other debris.

Wilson could have faced charges ranging from involuntary manslaughter to first-degree murder, and Brown's family said through their lawyers that they were "profoundly disappointed" by the grand jury's finding.

"While we understand that many others share our pain, we ask that you channel your frustration in ways that will make a positive change," the family said in a statement.

"We recognize that many people will want to second-guess the grand jury's decision. We would encourage anyone who wants to express an opinion do so in a respectful and peaceful manner," the statement said.

Attorneys for Wilson, who was placed on administrative leave and has avoided the spotlight since the shooting, said he was following his training and the law when he shot Brown.

As unrest flared following the announcement of the decision, Obama called for protesters to remain peaceful and for police to show restraint.

"We need to recognize that the situation in Ferguson speaks to broader challenges that we still face as a nation," the president told a televised news conference. "In too many parts of this country a deep distrust exists between police and communities of color."

The grand jury of nine whites and three blacks began meeting in late August and heard testimony from 60 witnesses called by the prosecution, including medical examiners who performed three autopsies.

St Louis County Prosecutor Bob McCulloch declined to say if the jury's decision was unanimous. At least nine jurors would have needed to agree to indict in order for Wilson to be charged.

A separate federal probe into the shooting is continuing, and US Attorney General Eric Holder emphasized that Justice Department investigators had not reached any conclusions.

Lawyers for Brown's family say the teen was trying to surrender when he was shot, while Wilson's supporters say the officer feared for his life and opened fire in self-defense.

Witnesses disagreed on whether Brown's hands were up at the time he was shot, McCulloch said, adding that Wilson shot at Brown 12 times.

Brown is suspected of having stolen cigars from a nearby convenience store shortly before the incident. Police said in August that Wilson was not aware of the robbery at the time.