A judge has temporarily blocked the Trump administration's plans to resume federal executions after 16 years, halting four scheduled executions to give the inmates time to challenge the new policy.

U.S. District Judge Tanya S. Chutkan said in a 15-page ruling issued in Washington, D.C. on Wednesday night, that one or more of the four men, all of them scheduled to be put to death at the federal penitentiary in Terre Haute, Indiana, were likely to prevail on their legal challenges to the policy.

She wrote that they would be "irreparably harmed" if they were executed before they had their day in court.

Legal challenges involving the common system of using three drugs to carry out lethal injections led to court rulings that effectively stopped federal executions in 2003. That was the last year a federal execution was carried out.

Criticism of the three-drug method peaked after a botched state execution in Oklahoma in 2014, which led President Barack Obama to order the Justice Department to review the use of lethal injection drugs.

In July, Attorney General William Barr directed the Justice Department to resume federal executions using a single drug, the barbiturate pentobarbital sodium. The federal Bureau of Prisons, or BOP, soon set execution dates for five men, including the four at Terre Haute.

Chutkan's order applies to those four men; the execution of the fifth man, the only Native American on death row, was separately stayed in October by a federal appeals court so it could consider his argument that he wasn't allowed to question jurors for potential racial bias.

In her ruling, Chutkan wrote that Barr's order conflicts with a 1994 federal law that specifies that federal executions must use the method "prescribed by the law of the State in which the sentence is imposed."

She rejected the Justice Department's argument that using a single drug in a state that uses three drugs was, in effect, close enough, writing that there was "no statute that gives the BOP or DOJ the authority to establish a single implementation procedure for all federal executions."

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Chutkan also spurned the government's argument that it would be harmed by delaying the executions, the first of which is scheduled for Dec. 9.

"The public interest is not served by executing individuals before they have had the opportunity to avail themselves of legitimate procedures to challenge the legality of their executions," she wrote.

"The public is not served by short-circuiting legitimate process, and is greatly served by attempting to ensure that the most serious punishment is imposed lawfully," she added.