Tsunami of anger hits US

The parents of Michael Brown have lashed out at the white police officer who shot dead their son, saying that he "wanted to kill someone" on the day he shot their unarmed black teenager.

Speaking after a grand jury cleared him of the August killing, officer Darren Wilson said he had "a clear conscience" and would have opened fire again if the confrontation on a Ferguson street was replayed.

His words were met with fury by protesters in the Missouri city and criticised by Michael Brown senior and Lesley McSpadden, the 18-year-old victim's parents.

"I don't believe a word of it," McSpadden said, when asked about the claim that her son had thrown the first punch and had been killed while charging down the street towards Wilson.

"[Wilson] didn't do what he had to do, he did what he wanted to do ... he wanted to kill someone."

McSpadden wept as she said that her son's body was left lying in the street in the summer heat for so long that his organs could not be donated.

As Brown's parents push for national legislation forcing police to wear cameras on their uniforms, Wilson said he was hoping one day to come out of hiding and resume a normal life.

The officer, who recently married and whose wife is pregnant, said Brown had tried to wrestle his gun out of his hands during a struggle and that he believed the 1.8m-tall teenager was capable of beating him to death.

"The reason I have a clean conscience is that I know I did my job right," he said.

Witnesses who testified before the grand jury offered different accounts of the shooting.

Some said Brown had his hands up in surrender when he died and others claimed that he charged at the police officer.

The US Justice Department is still investigating the case and federal prosecutors could, in theory, bring civil rights charges against Wilson, but that is considered unlikely.

Thousands of heavily armed National Guard troops and riot police surged on to the streets of Ferguson on Tuesday, preventing a second night of violence.

While there were intermittent clashes near the Ferguson police headquarters, there was no repeat of the arson and looting seen on Monday.

Protests against the jury's decision have taken place throughout the US. In Minneapolis, a woman was run over after a car ploughed into a line of protesters on Tuesday. The woman was dragged for several metres under the car's front left tyre but sustained only minor injuries.

The driver, a 40-year-old man, is cooperating with police and has not been charged.

In Ferguson, police arrested 45 people, mainly for minor offences, and said there was far less gunfire than the night before.

Soldiers armed with assault rifles and backed by armoured Humvees lined the streets.

Lyen Tam, owner of a Chinese takeaway, paused between serving a stream of customers to say that the troops' presence had made a difference. "We feel safer, especially when we're leaving," she said. "I wish they were here on Monday."

The St Louis region remained tense and two FBI agents were wounded during a shootout apparently unrelated to the Ferguson unrest.

Police also continued to investigate the murder of Deandre Joshua, a 20-year-old black man found dead in a car on Tuesday morning a few hundred meters from where Brown was killed.

Mass protests against the grand jury's decision reportedly spread to more than 100 cities - from New York to Los Angeles.

Thousands of demonstrators led to traffic jams in Manhattan, while in California protesters gathered around the Los Angeles Police Department headquarters.

In Cleveland, demonstrators blocked roads in protest at the death of Tamir Rice, a 12-year-old black boy killed by police at the weekend as he played with a toy gun.