President Barack Obama has commuted the sentence of Oscar López Rivera, who has been jailed for 35 years for a conviction on conspiracy charges related a series of bombings carried out by a Puerto Rican nationalist group. He is scheduled to be freed in about 4 months.
López Rivera, 74, was on a a list of pardons Obama issued. Obama's last day in office is Friday, when President-elect Donald Trump is to be sworn in.
Lopez Rivera long has denied involvement in the bombings that took place in the 1970s and 1980s. Lopez Rivera and his supporters have maintained there has never been evidence against him.
Lopez was convicted in 1981 of "seditious conspiracy" - trying to overthrow the government by force - and possession of firearms and transporting a stolen vehicle across state lines. Authorities labeled him a leader of the Armed Forces of National Liberation (FALN, in Spanish). The group claimed responsibility for the Chicago and New York bombings.
He was previously offered a commutation by former President Bill Clinton but turned it down.
Rep. Luis Gutierrez, D-Ill., said the release of López Rivera is "being celebrated by Puerto Ricans of all political stripes, classes colors and geographies." He said he was overjoyed with emotion when he got the news because Lopez is a friend and mentor.
"He is a national hero no less significant than Roberto Clemente or any leader we have ever had," Gutierrez said of Puerto Rico. "It will be a blessed day when I can walk and talk with my friend in the fresh air, far from prions walls, and I am looking forward to that day."
Lin-Manuel Miranda, the creator of the hit show "Hamilton" tweeted he was "sobbing" in London, where he is currently working.
His release has been championed by a number of supporters from Puerto Rico and the U.S. mainland. Former presidential candidate Bernie Sanders called for his release during the election campaign.
But there also has been opposition from families of victims of the bombing and law enforcement officials.
The son of a man killed in FALN's 1975 bombing in New York City's Fraunces Tavern told NBC News, "I'm disgusted the president could do this. I don't see any upside for the American people," said Tom Connor, 53, whose father Frank was one of 4 people killed in the blast.
"Letting loose terrorists at a time when terrorism is the biggest concern - what is it about Democratic presidents that they want to release terrorists?" Connor said.
Political strategist Federico de Jesús, who worked in the Obama administration, was part of a group of 40 former administration and campaign officials who sent the president a letter urging him to free López Rivera.
"We're very thankful that President Obama did the right thing, and elated that after 35 years of an excessive and unjust imprisonment, Oscar will finally be able to be home with his family," said de Jesús. "With this action, President Obama has given more meaning to his Nobel Peace Prize."
López Rivera was not scheduled for release until 2023.
NBC News writer Tracy Connor contributed to this report.