WASHINGTON — Justice Department officials have been weighing new guidance that would encourage prosecutors to charge suspects with the most serious offenses they can prove, a reversal of Obama-era policies that aimed to reduce the federal prison population and show more leniency to lower-level drug offenders.

If embraced by Attorney General Jeff Sessions, this could result in an increased use of rigid mandatory minimum sentences that critics have called unnecessarily harsh.

The guidance is taking shape in the form of a memo that ultimately will be shared with the nation’s federal prosecutors, but the time frame for release is unclear. Drafts of the memo have been circulating for weeks and have undergone revisions, so the final language is not yet certain.

A person involved in the discussions described one version to The Associated Press speaking only on condition of anonymity because the guidance has not been publicly announced. As outlined, that version would encourage prosecutors to charge people with the most serious, provable offenses — something more likely to trigger mandatory minimum sentences. Those rules limit a judge’s discretion and are typically dictated, for example, by the quantity of drugs involved in a crime.

Such a policy shift has been expected since Sessions was appointed and is in keeping with his tough-on-crime public posture, resistance to proposals he sees as overly lenient and repeated statements about running a Justice Department that enforces laws as they’re written. In 2003, Attorney General John Ashcroft enacted a similar policy that directed prosecutors to “pursue the most serious, readily provable offense in all federal prosecutions.”

The new policy statement is likely to represent a major departure from a 2013 initiative known as “Smart on Crime,” in which then-Attorney General Eric Holder discouraged harsh sentences for low-level, nonviolent offenders, which advocates say contributed to a national rethinking of how America’s drug criminals should be prosecuted.