(CNN) -- Nearly 3,100 federal inmates will walk out of prison on Friday as a provision of the sweeping criminal justice reform act passed by Congress takes effect.
The mass release -- the largest since the First Step Act was signed into law after a rare bipartisan push last year -- applies mostly to drug offenders and inmates serving sentences for weapons charges. It was initiated by a recalculation of the number of days inmates accrue each year for good behavior that was applied retroactively under the new law.
At a news conference at the Department of Justice Friday morning, Deputy Attorney General Jeffrey Rosen also announced that $75 million was being redirected from existing Justice Department programs to fund the First Step Act for the remainder of the fiscal year that goes through September, a move that could begin to allay the fears of some advocates who had questioned the department's commitment to reform.
"The attorney general and I both recently toured federal prisons and we saw first-hand the tremendous value in quality programs for inmates," Rosen said. "Using top-of-the-line research, people and technology, the Department intends to implement this law forcefully, fully and on time, with the goal of reducing crime, enhancing public safety and strengthening the rule of law."
So far, approximately 1,100 inmates that had been imprisoned on crack cocaine offenses have been released early as a result of sentence reductions brought about by the First Step Act, and hundreds more convicted of that crime are now looking towards a shorter prison term.
The act was signed into law by President Donald Trump in December after support from lawmakers across the aisle and personal attention from Trump's son-in-law and senior White House adviser Jared Kushner.
Not all of the 3,100 inmates being released from prison Friday will walk free. Some 900 prisoners will be transferred into state or immigration custody as a result of a detainer placed on them -- including 650 inmates that will be moved to Immigration and Customs Enforcement facilities and entered into deportation proceedings in accordance with their sentences, a Justice Department official said.
The Bureau of Prisons has coordinated with immigration authorities and local law enforcement ahead of the release, the official said.
The Department of Justice, under then-Attorney General Jeff Sessions, came out against the First Step Act as it was debated in Congress last year. Attorney General Bill Barr, who was confirmed after the reform became law, has pledged to fully implement it.
Justice officials on Friday also marked the rollout of a new risk and needs assessment system that prison officials will use to match inmates with recidivism programs that could help shave time off of their sentences -- a program that the law had mandated be announced by this week.
On Friday, criminal justice advocates praised the announcements but noted that more needed to be done to ensure the reform effort is fully funded and appropriately supervised.
"This is good news and we're happy to see that it's starting to be implemented but we think more needs to be done and we think Congress needs to provide that oversight," said Inimai Chettiar, the legislative and policy director of the Justice Action Network, a bipartisan advocacy group focused on the justice system.
Funding for the First Step Act had not been budgeted by lawmakers for this fiscal year, and appropriators have not yet established funding levels for 2020 yet.
The $75 million that the Justice Department will use to fund the reform programs this year will come from a combination of BOP inmate care programs and institutional administrative funding, the Justice official said, and Rosen said during the news conference that the department would work with Congress to ensure full funding in future years.