President Obama commuted the federal prison sentences of 61 drug offenders on Wednesday including more than a third serving life sentences, working to give new energy to calls for overhauling the U.S. criminal justice system.

All of the inmates are serving time for drug possession, intent to sell or related crimes. Obama's commutation shortens their sentences, with most of the inmates set to be released on July 28.

Obama, in a letter to those receiving commutations, said the presidential power to grand commutations and pardons "embodies the basic belief in our democracy that people deserve a second chance after having made a mistake in their lives that led to a conviction under our laws."

In a bid to call further attention to the issue, Obama planned to meet Wednesday with people whose sentences were previously commuted under Obama or Presidents Bill Clinton and George W. Bush.

The White House said the former inmates would share their experiences about the challenges of re-entering society after incarceration.

One of the inmates, Jesse Webster of Chicago, is serving a life term for intent to sell cocaine and filing false tax returns. Another, Byron McDade of Bowie, Md., got 27 years for cocaine-related charges as well.

In both cases, judges in the cases later said publicly it was too harsh, though sentencing guidelines often prevent judges from being more lenient. Webster and McDade will both be released later this year.

Most are nonviolent offenders, although a few also faced firearms charges. Nabar Criam of Brooklyn, N.Y., was sentenced to 15 years for possession of crack cocaine with intent to distribute, but received an additional charge for having a gun on hand during a drug trafficking crime.

The latest tranche of commutations brings to 248 the total number of inmates whose sentences Obama has commuted -- more than the past six presidents combined, the White House said. The pace of commutations and the rarer use of pardons are expected to increase as the end of Obama's presidency nears.

"Throughout the remainder of his time in office, the president is committed to continuing to issue more grants of clemency as well as to strengthening rehabilitation programs," said Neil Eggleston, the White House counsel, in a blog post.

He added that clemency is a tool of last resort that can help specific people, but doesn't address the broader need for a justice system that's "more fair and just."

Though there's wide bipartisan support in Congress for overhauling the criminal justice system, momentum has slowed as the chaotic presidential campaign has made cooperation between Republicans and Democrats this year increasingly difficult.

Obama has long called for getting rid of strict sentences for drug offenses that critics say lead to excessive punishment and sky-high incarceration rates. With Obama's support, the Justice Department in recent years has directed prosecutors to rein in the use of harsh mandatory minimums and expanded the criteria for inmates applying for clemency.