Officer Wilson is no-billed for murder.

UPDATE: More reactions around the country...

FERGUSON, Mo. (AP) — St. Louis County Police are confirming officers used tear gas to disperse crowds in Ferguson after a police car was vandalized, business windows shattered and gunshots were heard in the streets.

Some protesters erupted in anger after the announcement that Officer Darren Wilson won't be indicted in the shooting death of 18-year-old Michael Brown. Protesters overran a barricade and taunted police. Some chanted "murderer" and others threw rocks and bottles.

The windows of a police car were smashed and protesters tried to topple it before it was set ablaze. Officers responded by firing what authorities said was smoke and pepper spray into the crowd. St. Louis County Police later confirmed tear gas also was used.

Some in the crowd tried to stop others from taking part in the violence.

FERGUSON-Nationwide Protests

UNDATED (AP) — Thousands of people are rallying across the country to protest a grand jury's decision not to indict a white police officer who killed an unarmed, black 18-year-old in Ferguson, Missouri.

Activists had been planning to protest even before the nighttime announcement that Officer Darren Wilson will not be charged in the shooting death of Michael Brown.

Police in several cities took precautions but report the demonstrations have been largely peaceful.

Protesters blocked an intersection in downtown, Oakland, California. Some carried signs that read "The People Say Guilty!"

In San Francisco, a few dozen people gathered in the Mission District chanting "No justice, no peace!" There were similar shouts in downtown Philadelphia. There was a small brief rally near the federal courthouse in Pittsburgh.

In Los Angeles, there was a protest at a park.

UPDATE: President speaks out on Ferguson decision...

WASHINGTON (AP) — President Barack Obama says he joins with Michael Brown's family in urging peaceful protests after a grand jury decided not to indict the Ferguson police officer who shot and killed the unarmed, black 18-year-old.

Obama made the comments Monday moments after official word of the grand jury's decision.

The president said first and foremost the nation is built on the rule of law. He said despite anger and intense disagreement on either side, Americans need to accept the decision that the grand jury made.

The Justice Department is also conducting an investigation into possible civil rights violations that could result in federal charges.

UPDATE: Some violence reported in wake of decision...

FERGUSON, Mo. (AP) — Police cars have been vandalized and several gunshots have been heard on the streets of Ferguson after the announcement that a white police officer will not be indicted in the shooting death of an unarmed black 18-year-old.

About 15 minutes after St. Louis County Prosecutor Bob McCulloch announced Officer Darren Wilson wouldn't be indicted, county police used a bullhorn to tell crowds outside the Ferguson Police Department to disperse, saying it had become an unlawful assembly.

Protesters hugged a barricade and taunted police, sometimes with expletives. Some chanted "murderer." Gunshots were heard down the street and somebody threw a water bottle that bounced off a police shield.

Some in the crowd reportedly tried to stop others from taking part in vandalism and other violent reactions.

UPDATE: The family of Michael Brown has issued a statement...

FERGUSON, Mo. (AP) — Michael Brown's family issued this statement after a prosecutor announced that a grand jury has decided not to indict Ferguson Police Officer Darren Wilson:

We are profoundly disappointed that the killer of our child will not face the consequence of his actions.

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.

Join with us in our campaign to ensure that every police officer working the streets in this country wears a body camera.

We respectfully ask that you please keep your protests peaceful. Answering violence with violence is not the appropriate reaction.

Let's not just make noise, let's make a difference.

FERGUSON (AP) - A grand jury has decided not to indict Ferguson police officer Darren Wilson in the death of Michael Brown, the unarmed, black 18-year-old whose fatal shooting sparked weeks of sometimes-violent protests.

St. Louis County Prosecuting Attorney Bob McCulloch announced the decision Monday evening. A grand jury of nine whites and three blacks had been meeting weekly since Aug. 20 to consider evidence.

At least nine votes would have been required to indict Wilson.

The Justice Department is conducting an investigation into possible civil rights violations that could result in federal charges.

Brown's Aug. 9 death sparked more than a week of unrest that included angry clashes between police and protesters and led Missouri Gov. Jay Nixon to briefly summon the National Guard.