Attorney General Michael Mukasey sought to enlist police Monday in his fight against changes in federal sentencing rules that reduce prison time for thousands of crack cocaine offenders whom he described as repeat criminals.

New data from the U.S. Sentencing Commission indicate that in the first wave of 1,500 crack convicts who are slated for release as early as next week, one-third have little or no criminal history.

In remarks to the Fraternal Order of Police, Mukasey used a Sentencing Commission report from last year to bolster his long-standing warning against letting crack cocaine offenders out of prison early. He said nearly 80 percent of the total estimated 19,500 crack convicts who could apply for reduction in their sentences have some kind of criminal past.

"This tells us those who are eligible for early release are very likely to commit another crime," Mukasey said in brief remarks to the police officers, in town for several days to lobby Congress. "These offenders are often violent criminals who are likely to repeat their criminal activities."

The Sentencing Commission in December unanimously approved changes to federal sentencing guidelines to ease a disparity between harsh penalties for crack offenses compared to the relatively shorter prison time for powder cocaine violations.

Four of every five crack defendants are black, while most powder cocaine convictions involve whites.

Under the guidelines, set to take effect March 3, just over 1,500 crack offenders could apply for immediate release, while the rest could be eligible for shorter sentences over the next 30 years.

According to the Sentencing Commission's recent data, a look at the 1,508 crack offenders eligible for immediate release shows that 32 percent of them have either been convicted of one crime or committed none previously at all.

The commission data for the first wave of crack releases, provided by Rep. Bobby Scott, D-Va., suggest that 90 percent were nonviolent and only 32 percent of them involved guns or other weapons.

Scott is among more than a half-dozen lawmakers who are pushing for legislation to erase any disparity between crack and powder cocaine penalties. Sen. Joe Biden, D-Del., is backing similar plans in the Senate.

Mukasey has said he is willing to address the disparity — but only if Congress restricts the retroactive sentence reductions for first-time, nonviolent offenders only.

A House Judiciary subcommittee hearing Tuesday will look at changes to the guidelines — and possible ways to roll back penalties for crack offenders even more dramatically.

"Far too many people have been victimized by an unjust sentencing system for 20 years now," said Marc Mauer of the Sentencing Project, an advocacy group. "The time is long past for Congress to fix this sentencing disparity."