A grand jury in Missouri refused to indict St. Louis County police officer Darren Wilson in the alleged shooting death of an unarmed 18-year-old black man.

Jurors had been for months pouring over every single piece of evidence available in the case, prosecutors have said, a rare move that underscores the racial tensions in the suburban community.

Missouri Gov. Jay Nixon, during a press briefing today, pleaded for "peace, respect, restraint" in the run-up and aftermath of the announcement. In the days and weeks after the shooting, Ferguson businesses and streets were the scene of rampant looting and often violent protests.

The racially charged case has inflamed tensions and reignited debates over police-community relations in many cities.

Nixon was flanked by the state's public safety director and leaders from St. Louis city and county. They said peaceful protesters will be respected, and even allowed to potentially slow down traffic on streets.

But state and local leaders said they will not tolerate the destruction of property or violence. Nixon last week declared a state of emergency and activated the National Guard.

Protesters across the nation were planning demonstrations to coincide with tonight's announcement, even before they knew whether or not the grand jury would indict Wilson.

Wilson is the white suburban St. Louis police officer who is accused of shooting to death Michael Brown, an 18-year-old black man, after a confrontation in August.

Clergy are planning to hold a gathering at a church in Denver, where a jury found deputies used excessive force in the death of a homeless street preacher.

In Cleveland, at least a dozen protesters held signs and chanted about recent police shootings there.

The Associated Press contributed to this post. 

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