President Trump threw his support behind a bipartisan bill to reform federal sentencing guidelines Wednesday, which he said would "reduce crime while giving our fellow citizens a chance at redemption."

"We’re all better off when former inmates can receive and re-enter society as law-abiding, productive citizens," Trump said in brief remarks in the Roosevelt Room of the White House. "And thanks to our booming economy, they now have a chance at more opportunities than they’ve ever had before."

The so-called First Step Act, the first major rewrite of the nation's criminal justice sentencing laws in a generation, will boost rehabilitation efforts for federal prisoners and give judges more discretion when sentencing nonviolent offenders, particularly for drug offenses. In particular, the bill lowers the mandatory minimum sentence for non-violent repeat drug offenders from 25 to 20 years, reduces mandatory minimums for other crimes from 20 to 15 years, and makes no distinction between powder cocaine and crack cocaine.

"Americans from across the political spectrum can unite around prison reform legislation that will reduce crime while giving our fellow citizens a chance at redemption," said Trump, who at one point joked: "Did I hear the word bipartisan? Did I hear that word? That's a nice word."

Trump singled out his son-in-law, White House senior adviser Jared Kushner, for special praise during his remarks and noted that he had "worked very hard" and "feels very deeply" about the issue.

"It's my honor to be involved, and it'll be an even greater honor to sign it," said the president, who urged Congress to pass the measure quickly during the lame-duck session of Congress, proclaiming: "I'll be waiting with a pen."

Senate Majority Leader Mitch McConnell, R-Ky. was cautious about the bill's prospects Wednesday. He told reporters that GOP leaders would do a whip count to gauge the bill's support once they have a final proposal in hand.

Still, he noted the Senate has other things it needs to accomplish in the final weeks of the year, including funding the government and passing a farm bill. He said Republicans would have to see how the criminal justice bill "stacks up against our other priorities" once a final agreement is reached.

"We don't have a whole lot of time left, but the first step is to finalize what proponents are actually for," McConnell said. "There have been a lot of different versions floating around. And then we'll whip it and see where the vote count is and then see how it stacks up against our other priorities going on here to the end of the session."

The Senate package overhauls some of the mandatory sentencing guidelines that have been in place since 1994 legislation approved by Congress and signed into law by then-President Bill Clinton. Trump made a point of mentioning that fact in his remarks Wednesday, adding that the Clinton-era guidelines "disproportionately hurt the African-American community." He also noted that several law enforcement organizations supported the effort, saying: "In many respects, we’re getting very much tougher on the truly bad criminals, which, unfortunately, there are many. But we’re treating people differently for different crimes."

Sens. Chuck Grassley, R-Iowa, and Dick Durbin, D-Ill., called Trump's endorsement "an important step in our shared effort to promote safe communities and improve justice." Grassley, the chair of the Senate Judiciary Committee, and Durbin, the Senate's second-ranking Democrat, have led the bipartisan effort to overhaul the guidelines. The bill has also attracted support from a coalition of liberal and conservative groups, including the American Civil Liberties Union and groups backed by the political donors Charles and David Koch.

The House approved a prison reform bill in May, but the Senate package makes additional changes and adds the sentencing component.

House Speaker Paul Ryan, R-Wis., called Trump's announcement "an encouraging sign that we can achieve substantive reforms to our criminal justice system in this Congress."

"Redemption is at the heart of the American Idea, and that's what this is about," he said.

The Senate approach would allow thousands of federal prisoners sentenced for crack cocaine offenses before August 2010 the opportunity to petition for a reduced penalty. It would also lower mandatory minimum sentences for some drug offenses. The life sentence for some drug offenders with three convictions, or "three strikes," would be reduced to 25 years.

Roughly 90 percent of prison inmates are held in state facilities and would not be affected by the legislation.

All but two Republicans voted for the House bill when it was overwhelmingly approved in May, 360-59. Democratic lawmakers supported the bill by about a 2-to-1 margin, but opponents voiced concerns that it did not go far enough in giving judges more discretion to make the punishment fit the crime.

The House bill directs the Bureau of Prisons to conduct assessments for every offender once he or she is sentenced and to offer rehabilitation plans designed to lower the chance of recidivism. The plans would include vocational training, education, counseling and substance abuse treatment.

The federal inmate population has been on the decline since 2013, when it peaked at just more than 219,000. The total now stands at about 181,400, according to the Federal Bureau of Prisons. Still, that's about triple the number of inmates in federal detention 30 years ago.

The Associated Press contributed to this report.