WASHINGTON (Reuters) - U.S. President Barack Obama shortened the prison sentences for 98 convicts serving time for drug-related offenses in his latest round of commutations, including for 42 people serving life sentences, the White House said on Thursday.

Obama has granted 688 commutations this year, for a total so far of 872 during his presidency, which ends on Jan. 20.

"These are individuals - many of whom made mistakes at a young age - who have diligently worked to rehabilitate themselves while incarcerated," White House Counsel Neil Eggleston said in a statement.

The commutations are part of Obama's push to reform the criminal justice system to reduce the number of people serving long sentences for non-violent drug offenses.

Obama and a bipartisan group of lawmakers in the U.S. Congress had tried to work on legislation to reduce mandatory minimum sentences, but those efforts stalled ahead of the Nov. 8 presidential election.

(Reporting by Roberta Rampton; Editing by James Dalgleish)