LINCOLN, Neb. (AP) — Long prison sentences and mandatory minimums are major contributors to Nebraska’s chronic prison overcrowding, according to a report released Thursday, but lawmakers made clear that they disagree over how to fix the problem.

The report by the Crime and Justice Institute was requested by Nebraska lawmakers, Gov. Pete Ricketts and the courts to try to identify ways to reduce the state’s inmate population without compromising public safety.

Len Engel, the institute’s policy and campaigns director, said his group found that Nebraska’s prison population increased 21% over the last decade, likely because of tough-on-crime policies from the 1970s, 80s and 90s. The institute also found that low-level, non-violent felony sentences were often imposed consecutively, resulting in longer prison terms.

Sen. Suzanne Geist, of Lincoln, said she was concerned that the report could be used to promote policies that jeopardize public safety. She said some inmates were convicted of low-level felonies because of plea bargains that allowed them to avoid more serious charges.

Sen. Steve Lathrop, chairman of the Judiciary Committee, said the report produced some recommendations where all stakeholders agreed and others where lawmakers “will have a serious policy debate.”