Attorney General Jeff Sessions announced Friday that he has told prosecutors to pursue the most serious charges possible against criminal suspects – a stunning reversal of Obama-era policies, and a move that infuriated civil rights groups.

“We will enforce the laws passed by Congress pure and simple,” he said at an awards ceremony in Washington D.C, adding that prosecutors deserved to be “unhandcuffed and not micro-managed from Washington.”

“This is a key part of President Trump’s promise to keep America safe,” Sessions said. “We’re seeing an increase in violent crime in our cities – in Baltimore, Chicago, Memphis, Milwaukee, St. Louis and many others. The murder rate has surged 10 percent nationwide – the largest increase since 1968.”

In a letter to 94 U.S. attorneys Thursday night, Sessions called it a “core principle” that prosecutors charge and pursue “the most serious and readily provable offense.” Sessions defined the most serious offenses as those that carry the most substantial guidelines sentence.

Sessions noted that “there will be circumstances in which good judgment would lead a prosecutor to conclude that a strict application” of the policy is not warranted, but that any exceptions must first be approved by a U.S. attorney, assistant attorney general, or a designated supervisor.

The move, which will send more criminals to jail and for longer terms by triggering mandatory minimum sentences, explicitly reverses policies set in motion by President Obama’s former Attorney General Eric Holder – who implemented the “Smart on Crime” drug sentencing policy that focused on not incarcerating people who committed low level, non-violent crimes. DOJ officials call it a “false narrative” and say unless a gun is involved, most of those cases aren’t charged period.

Officials say Holder’s “Smart on Crime” policy “convoluted the process,” and left prosecutors applying the law unevenly, which they said “is not Justice.”

But civil rights groups blasted the process, with the American Civil Liberties Union describing the move as a move that will “reverse progress” and repeat the War on Drugs, which it called a “failed experiment.”

“With overall crime rates at historic lows, it is clear that this type of one-dimensional criminal justice system that directs prosecutors to give unnecessarily long and unfairly harsh sentences to people whose behavior does not call for it did not work,” Udi Ofer, director of the American Civil Liberties Union’s Campaign for Smart Justice.

The policy was also criticized by Sen. Rand Paul, R-Ky., who said mandatory minimums have “unfairly and disproportionately incarcerated too many minorities for too long.”

“Attorney General Sessions new policy will accentuate that injustice. Instead we should treat our nation’s drug epidemic as a health crisis and less as a lock ‘em up and throw away the key problem,” he said.

However, the National Association of Assistant United States Attorneys backed the move, saying it would make the public safer and give prosecutors to “tools that Congress intended” to lock up drug dealers and dismantle gangs.

Fox News’ Jake Gibson and The Associated Press contributed to this report.