President Obama asked Americans to show restraint and calm in the aftermath of a St. Louis County grand jury’s decision not to file charges against a white police officer who fatally shot unarmed black teen Michael Brown Monday night.

Obama also acknowledged the situation highlights a deep mistrust for law enforcement rooted in decades of racial discrimination.

“We are a nation built on the rule of law,” the president said from the White House minutes after the decision was announced. “I join Michael’s parents in asking people to protest peacefully. … There is never an excuse for violence.”

Obama said he understood that Americans might be angry that Ferguson, Mo., police Officer Darren Wilson will not face state charges in the Aug. 9 incident but urged people across the country not to respond by “vandalizing, hurting anybody.”

The president suggested that Americans, particularly minorities, think the law is often being applied unfairly and that law enforcement needs more and better training so that it can “conduct itself in a way that’s fair.”

The president did not say whether he would go to Ferguson but that Attorney General was already there.

Holder said an independent Justice Department investigation into the incident continues, and he echoed Obama’s call for calm and his concerns about Americans’ discontent with law-enforcement agencies across the country.

“This incident has sparked a national conversation about the need to ensure confidence between law enforcement and the communities they protect and serve,” Holder said in a statement. “While constructive efforts are underway in Ferguson and communities nationwide, far more must be done to create enduring trust.”

Holder said his department will continue to work with law enforcement, civil rights, faith and community leaders to “improve fairness in the criminal justice system overall” and investigate allegations of unconstitutional policing patterns or practices by the Ferguson Police Department.

On Capitol Hill, Missouri Democratic Rep. William Lacy Clay called the grand jury’s decision “extremely disappointing, but not unexpected.”

“From the beginning of this tragic case, I have repeatedly expressed my grave concerns about the local investigation,” Lacy said in a statement. “Sadly, we see that those concerns were well founded.”

Lacy also said he has Holder’s assurance that the federal investigation will be “extensive, vigorous” and will follow the facts.

“The pursuit of justice for Michael Brown Jr. and his family is not over,” Lacy said.

Ohio Democratic Rep. Marcia L. Fudge, chairwoman of the Congressional Black Caucus, called the grand jury’s decision a “miscarriage of justice” and a “slap in the face to Americans nationwide who continue to hope and believe that justice will prevail.”

"This decision seems to underscore an unwritten rule that Black lives hold no value; that you may kill Black men in this country without consequences or repercussions,” Fudge also said, in a statement.

Missouri Republican Sen. Roy Blunt said Brown’s death is “a tragic loss” and that he joins the Brown family in “urging protestors to do so peacefully.”

Blunt also said officers could have better handled the angry protests in Ferguson in the days after Brown’s death, based on extensive talks with law-enforcement officials about the tactics, resources and procedures of first-responders across Missouri. He said he trusted the recommendations will be helpful “as we continue to count on them to protect us.”