Several American cities, including Ferguson, Los Angeles, Seattle and New York, on Monday night witnessed protests and violence as people reacted to a grand jury’s decision not to prosecute a white police officer, Darren Wilson, who killed defenseless black 18-year-old Michael Brown in Ferguson, Missouri, in August.

The angry protesters invaded barricades placed by police in Ferguson, with some shouting murderer and others throwing rocks and bottles at the security operatives.

Angry residents in Ferguson also set businesses and two police cars on fire and the St. Louis police chief, Jon Belmar, said about 29 persons had been arrested in connection with the violence.

Ferguson police officers fired at the protesters what authorities said was smoke and pepper spray to disperse them as some in the crowd tried to stop others from taking part in the violence.

Police who formed a wall of clear riot shields outside the area were bombarded with bottles and cans as the crowd rushed up and down the street soon after authorities said the grand jury had voted not to indict Wilson.

In Seatle, Washington, protesters pelted police officers with rocks, bottles and cans and had to be controlled with pepper sprays.

In New York over a thousand people held a peaceful protest around the Times Square.

The deceased family, in a statement released shortly after the decision of the Jury was made public, urged a non-violent response to the grand jury’s decision.

“We are profoundly disappointed that the killer of our child will not face the consequence of his actions,” the statement said.

“While we understand that many others share our pain, we ask that you channel your frustration in ways that will make a positive change. We need to work together to fix the system that allowed this to happen,” the statement added.

Wilson’s attorneys hailed the grand just decision, saying that it only agreed with their own position that the officer acted “in accordance with the law and the regulations that govern the procedures of an officer.”

In a statement released on Monday night after the grand jury decision was announced, the attorneys said, “Law enforcement personnel must make split – second and difficult decisions. Officer Wilson followed his training and followed the law.”

Ahead of Monday’s announcement, Missouri Governor, Jay Nixon had declared a state of emergency in the area and called in 400 National Guard troops in anticipation of protests.

Authorities however called for patience and assured residents that the National Guard would provide security at critical facilities like fire houses, police stations and utility substations.

Meanwhile, President Barack Obama has urged Americans to accept that the decision was the call of the grand jury, as he called those who wanted to protest against it to do so calmly.

The case has fueled racial tensions in the US, with several people in the African American community calling for Wilson to be charged with murder.

Michael Brown was killed by Darren Wilson in Ferguson on August 9, with his death sparking off weeks of demonstrations in Ferguson and other U.S. cities.