The US government will resume capital punishment after a 16-year hiatus and has set execution dates for five murderers, Attorney General William Barr announced on Thursday.
Acting on President Donald Trump's call for tougher penalties on violent crimes, Mr Barr directed the Federal Bureau of Prisons to adopt a lethal injection protocol.
"The Justice Department upholds the rule of law and we owe it to the victims and their families to carry forward the sentence imposed by our justice system," he said.
There were 25 executions in the US last year, all carried out by state authorities on people convicted of state charges.
But debate about the methods of execution and controversy over the drugs used, and reticence from Mr Trump's predecessor Barack Obama, means no federal prisoner has been put to death since 2003.
Mr Barr ordered the bureau to carry out executions using a single lethal injection of the barbiturate pentobarbital, replacing the previous three-drug cocktail.
"Since 2010, 14 states have used pentobarbital in over 200 executions, and federal courts including the Supreme Court have repeatedly upheld the use of pentobarbital in executions as consistent with the Eighth Amendment", which bars cruel and unusual punishment, the Justice Department said.
There are 62 federal death row prisoners in the US, the Death Penalty Information Centre said.
They include Dzhokhar Tsarnaev, who was convicted of the 2013 Boston Marathon bombing that killed three people.
It also includes white supremacist Dylann Roof, who murdered nine African-Americans in a Charleston, South Carolina church in 2015.
On Mr Barr's order, the bureau has scheduled executions for five people all convicted at least 15 years ago in brutal murders involving children.
They include Daniel Lewis Lee, who robbed and killed a family of three including an 8-year-old girl in 1996, and Alfred Bourgeois, who tortured and sexually molested his daughter, 2, before killing her in 2002.
Federal executions were on hold for nearly four decades until 2001, when Oklahoma City bomber Timothy McVeigh was executed.
Two more people were put to death in federal prisons over the following two years before federal executions were halted again.
Since then all executions have been carried out by states. Twenty-five of the 50 US states still have an active death penalty, while 21 do not allow it and four have suspended its use.
Mr Obama, president from 2009 to 2017, called the practice "deeply troubling".
He pointed to the disproportionately high number of African-Americans sentenced to death, and recent "rather gruesome and clumsy" executions by states.
The Justice Department has pressed to toughen punishments for violent crimes since Mr Trump took office, but Mr Barr's move also comes as the president seeks to bolster his law-and-order credentials ahead of next year's election.
In October 2017, Mr Trump called for the execution of Sayfullo Saipov, the ISIS-inspired Uzbek immigrant accused of a lorry attack on pedestrians in New York in October 2017, which killed eight people.
He repeated that call after a white nationalist killed 11 in October 2018 in a Pittsburgh synagogue.
Both of those cases remain in the courts.
Death penalty opponents blasted the policy change and called for a court-ordered delay in the executions, the first of which is scheduled for early December.
"The federal death penalty is arbitrary, racially biased, and rife with poor lawyering and junk science," said Ruth Friedman, director of the Federal Capital Habeas Project.
"These and other concerns, including troubling questions about the new execution protocol, are why there must be additional court review before the federal government can proceed with any execution."
Morris Moon, a lawyer for Mr Lee who is due to be executed on December 9, said the case was based on unreliable evidence and that Mr Lee's accomplice in the crime killed the child and was sentenced to life in prison.
"The trial judge, the lead prosecutor and members of the victims' family all oppose executing him, and believe a life sentence is appropriate," Mr Moon said.
"Given the problems that undermine the fairness and reliability of Danny Lee's conviction and death sentence, the government should not move forward with his execution."
