Protesters blocked a freeway in California and basketball stars in New York wore shirts invoking the last words of Eric Garner, a black man who died after a police chokehold, amid racially charged protests Monday over a grand jury's failure to indict the white officer involved.

Cleveland Cavaliers forward LeBron James and other players wore T-shirts emblazoned with the words "I CAN'T BREATHE" in pre-game warmups at the Barclays Center in Brooklyn, where Britain's Prince William and his wife Kate were among thousands who came to see the team play the Brooklyn Nets.

Also on Monday, New York State's top prosecutor sought the power to probe all police killings of unarmed civilians in his state, following sometimes violent US protests after two grand juries declined to indict officers in the deaths of unarmed black men.

"The horrible events surrounding the death of Eric Garner have revealed a deep crisis of confidence in some of the fundamental elements of our criminal justice system," New York Attorney General Eric Schneiderman said in a statement. "Nothing could be more critical for both the public and the police officers who work tirelessly to keep our communities safe than acting immediately to restore trust."

Cities across the United States have seen large protests in recent nights following the failure to indict anyone over the death in July of Garner, an unarmed black father of six, which happened after police put him in a banned chokehold.

The decision in the Garner case came little more than a week after a Missouri grand jury cleared an officer in the fatal August shooting of an unarmed black teen, Michael Brown.

In the California college town of Berkeley, near San Francisco, businesses closed early and officials at the University of California urged calm a day after protesters hurled rocks and other objects at police who responded with tear gas. The student advocate's office at the University of California, Berkeley, said on Twitter it would distribute kits including water, disinfectant wipes, masks and gauze in advance of more protests scheduled for Monday night.

Several hundred protesters roamed Berkeley streets on Monday night, intermittently blocking roads and a freeway.

Outside Barclays Center, a group of about 300 protesters blocked streets and chanted, "I can't breathe," in memory of Garner, and "Hands up, don't shoot," a reference to Brown's death in the St. Louis suburb of Ferguson.

Some in the crowd rushed to the barricades in front of Barclays Center as ticket-holders waited to go in. A small group entered a Target store, but left after police officers moved in.

It remained unclear whether New York Governor Andrew Cuomo would grant Schneiderman the powers he is seeking. Like the Democratic mayor of New York, Cuomo has tried to walk a fine line between expressing concern about a grand jury's decision not to charge a police officer in the death of Garner without alienating police.

"We are reviewing the attorney general's proposal," said Cuomo spokeswoman Melissa DeRosa, adding that the governor plans a "top to bottom review" of the system.

The order, if signed, would only affect new cases of unarmed civilians killed by police, not Garner or Akai Gurley, 28, whom a police officer shot dead in the dark stairway of a Brooklyn apartment building last month.

US Attorney General Eric Holder, whose office is investigating the Garner case, on Monday unveiled a set of changes to federal law enforcement guidelines intended to set an example for local police, according to a Justice Department official.

Several members of the New York City Council joined in the protests on Monday, when they staged a "die-in" on the steps of City Hall, over the decision not to indict Garner.

In Cleveland, where the US Justice Department last week said police routinely use excessive force, Samaria Rice, the mother of a 12-year-old African-American boy shot dead by police in November, spoke to the media on Monday for the first time since her son's death.

Rice's son, Tamir Rice, was shot near a recreation center while carrying a pellet gun that was a replica of a real gun. The boy's family has filed a federal civil rights lawsuit against the city and the two officers involved, one who shot Rice on November 22 and one who was driving the police car.

"I'm actually looking for conviction," Rice told reporters. "Tamir was a bright child, he had a promising future and he was very talented in all sports: soccer, basketball, football. He was my baby."

BERKELEY RIOTS

Police in Berkeley, California, on Monday said they made five arrests during Sunday night protests, when a crowd of more than 500 people threw rocks and other objects at police and a number of stores were looted. One protester who tried to prevent the looting was assaulted, police said.

The two nights of looting on the West Coast contrasted with mostly peaceful demonstrations elsewhere around the United States after the decision not to indict New York Police Department officer Daniel Pantaleo for the death of Garner, 43.

While no criminal charges have been brought, the NYPD is conducting an internal investigation into the case. The probe into whether Pantaleo broke any department rules could take four months, officials have said. The Justice Department is also investigating the case.