US President Joe Biden is facing growing calls to commute the death sentences of the more than three dozen federal inmates on Death Row before Donald Trump returns to the White House.

Trump resumed federal executions during his last term in office, overseeing 13 by lethal injection during his final six months in power, more than any US leader in 120 years.

Biden campaigned for the White House as an opponent of the death penalty and the Justice Department issued a moratorium on its use at the federal level after he became president.

During his re-election campaign against Kamala Harris, Trump spoke frequently of expanding the use of capital punishment to include migrants who kill American citizens and drug and human traffickers.

There had been no federal inmates put to death in the United States since 2003 until Trump resumed federal executions in July 2020.

A coalition of death penalty opponents submitted a letter to Biden on Monday asking him to commute federal death sentences to life in prison without parole.

"The only irreversible action you can take to prevent President-elect Trump from renewing his execution spree, as he has vowed to do, is commuting the death sentences of those on federal death row now," the American Civil Liberties Union, Amnesty International, Human Rights Watch and more than 130 other organisations said.

"Your ability to change the course of the death penalty in the United States will be a defining, legacy-building moment in American history," they said.

There are currently 40 prisoners - all men - convicted of federal crimes awaiting execution, according to the Death Penalty Information Center, including several in high-profile cases.

They include:

- Dzhokhar Tsarnaev, 31, the "Boston Bomber," who was sentenced to death for the murders of two people in the April 15, 2013 bombing of the Boston Marathon.

- Dylann Roof, 30, an avowed white supremacist who shot dead nine Black parishoners during a June 17, 2015 Bible study meeting at a church in Charleston, South Carolina.

- Robert Bowers, 52, an anti-Semitic Pennsylvania man who killed 11 Jewish worshippers during an October 27, 2018 attack on the Tree of Life synagogue in Pittsburgh.

Commuted, changed

Nine of the inmates on federal Death Row were convicted of murdering fellow prisoners while one killed a prison guard.

Four were sentenced to death for murders committed during bank robberies.

There are also four inmates on the military's Death Row including Nidal Hasan, a US Army psychiatrist who shot dead 13 people during a rampage at Fort Hood, Texas, in 2009.

The US military has not carried out an execution since 1961.

Pope Francis, in his Sunday address at the Vatican, asked the crowd to pray for Death Row inmates in the United States and said their sentences should "be commuted, changed."

Biden, who controversially pardoned his son Hunter this month for tax and gun crimes, has been barraged with clemency appeals from other religious leaders, former state and federal prison officials, ex-prosecutors and dozens of relatives of murder victims.

Richard Branson, the Virgin Group founder, and Sheryl Sandberg, a former top executive at Facebook, were among the signatories of a letter from top business leaders urging Biden to exercise his clemency power.

According to The Washington Post, the White House is considering "taking steps to commute at least some federal death sentences."

"No decision has been made, however, about the breadth or scope of such a possible move, including whether to do it at all," the newspaper said.

There have been 23 executions in the United States in 2024 and two more are scheduled before the end of the year.

The death penalty has been abolished in 23 of the 50 US states, while six others - Arizona, California, Ohio, Oregon, Pennsylvania and Tennessee - have moratoriums in place.

Federal executions are carried out by lethal injection at a prison in Terre Haute, Indiana. The last one was on January 16, 2021, four days before Trump left office.

AFP