Angry crowds poured into the streets of Ferguson, Missouri last night within minutes of news that a grand jury decided not to indict a white police officer over the death of unarmed black 18-year-old.
Violence erupted quickly after demonstrators learned there would be no criminal indictment of policeman Darren Wilson for the August shooting death of teen Michael Brown.
Demonstrators taunted police, shattered windows and set fire to two St Louis County police cars.
Scattered, intermittent gunfire was also reported, but it mostly disappeared by Tuesday morning.
St Louis County Police Chief Jon Belmar said at a news conference that at least a dozen buildings were burning and that he had heard at least 150 gunshots, none fired by police.
A police officer was shot but not seriously hurt, Belmar said.
Police had made 29 arrests.
"I'm disappointed this evening," Belmar said. "What I've seen tonight is probably worse than the worst night we had in August."
He said protesters could not be controlled "unless we bring 10,000 policemen in here."
Scores of police officers, armed with riot gear, dispersed a crowd of about 300 with volley after volley of tear gas, pepper spray and bean bags. But not before looters plundered a Walgreen store, Family Dollar store and an Autozone outlet. Other protesters torched a Little Casears pizza restaurant and local beauty shop - among several buildings set ablaze that were continuing to light up the sky.
Two police cars were burned.
The chaos grounded flights in and out of St Louis' Lambert International Airport airlines until early this morning, to provide a safe environment for law enforcement activities, the Federal Aviation Administration said.
Much of the crowd had been dispersed by about midnight. There were no other official reports of arrests or injuries.
There was also looting at several businesses after the Ferguson protests turned violent.
Multiple fires burned early today, including at storage facility, car parts stores and a beauty supply shop. An AP photographer saw firefighters arrive at one scene only to be turned back by gunfire.
Not long after it was announced that Officer Darren Wilson would not be indicted, protesters smashed a police car's windows and tried to topple it before it was set ablaze. Some in the crowd tried to stop others from taking part.
Officers lobbed smoke, pepper spray and tear gas from inside armoured vehicles to break up the crowds.
Wilson's fatal shooting of Brown during an August 9 confrontation sparked a fierce debate over how police treat young African-American men.
It focused attention on long-simmering racial tensions in Ferguson and around the US, four decades after the 1960s civil rights movement.
Police were criticised for responding to mostly peaceful protests with armoured vehicles and tear gas.
Police departments in several big cities are now bracing for large demonstrations with the potential for violence.
Yesterday housands of people protested from Los Angeles to New York, leading marches, waving signs and shouting chants of the slogan "Hands Up! Don't Shoot."
In New York, a crowd wound its way through the city, surging to more than 1,000 in Times Square before heading toward the Upper West Side.
Earlier in the evening, about 200 people flocked to Union Square, brandishing signs that read, "Jail killer cops," and a large display, in lights: "Black lives matter."
In Oakland, California, shop owners posted signs in their windows, "We support Michael Brown," as marchers took to the streets.
A crowd filled the intersection at 14th and Broadway, and some demonstrators laid their bodies down in chalk outlines, reports on social media showed.