The US attorney general has ordered a pause on federal executions that were resumed in 2020 under the Trump administration after a 17-year hiatus.
Merrick Garland, the US government’s top lawyer, also ordered a review of the rules around the death penalty.
The decision had the backing of President Joe Biden, who appointed Mr Garland vowing to pause executions.
The Trump administration carried out 13 federal executions during the former president’s final months in office.
In issuing the moratorium, Attorney General Garland cited the disproportionate number of racial minorities who are sentenced to capital punishment.
“The Department of Justice must ensure that everyone in the federal criminal justice system is not only afforded the rights guaranteed by the constitution and laws of the United States, but is also treated fairly and humanely,” Mr Garland said.
No federal inmates have been put to death since Mr Biden took office. There are about 50 people currently on federal death row, according to the non-partisan Death Penalty Information Center.
Executions had been ordered to resume in 2020 by former Attorney General William Barr, who argued that the federal government owed “the victims and their families to carry forward the sentence imposed by our justice system”.
Mr Garland also ordered officials to review the drugs administered during lethal injection amid reports that prisoners may have experienced severe pain while dying.
The majority of US executions are administered by states, where some 2,500 prisoners are on death row. Texas leads the country with 570 executions since 1976.
As a candidate Mr Biden promised to end federal executions, and encourage states to also end the practice. Already nearly half of states have abolished the death penalty.