WASHINGTON, United States (AP) — A federal judge has temporarily halted the first federal execution in 16 years as a lawsuit on how the government intends to carry it out continues.

US District Judge Tanya S Chutka said in a Wednesday evening ruling that the public is not served by “short-circuiting” legitimate judicial process.

“It is greatly served by attempting to ensure that the most serious punishment is imposed lawfully,” she wrote.

Attorney General William Barr unexpectedly announced in July that the government would begin resuming executions starting December 9, ending an informal moratorium on federal capital punishment as the issue receded from the public domain. The Justice Department didn’t immediately return a call seeking comment on Thursday, and the attorney general was travelling.

Most Democrats oppose the death penalty. By contrast, President Donald Trump has spoken often about capital punishment and his belief that executions serve as an effective deterrent and an appropriate punishment for some crimes, including mass shootings and the killings of police officers.

Still, executions on the federal level have been rare. The government has put to death only three defendants since restoring the federal death penalty in 1988, most recently in 2003, when Louis Jones was executed for the 1995 kidnapping, rape and murder of a young female soldier.

In 2014, following a botched state execution in Oklahoma, President Barack Obama directed the Justice Department to conduct a broad review of capital punishment and issues surrounding lethal injection drugs.

Barr said in July that the Obama-era review had been completed, clearing the way for executions to resume.

He approved a new procedure for lethal injections that replaces the three-drug combination previously used in federal executions with one drug, pentobarbital. This is similar to the procedure used in several states, including Georgia, Missouri and Texas.

Some of the chosen convicts challenged the new procedures in court, arguing that the government was circumventing proper methods to wrongly execute inmates quickly.

Danny Lee, of Yukon, Oklahoma, was the first person scheduled to be executed. Lee was convicted in the 1996 deaths of an Arkansas family as part of a plot to set up a whites-only nation in the Pacific Northwest.

“This decision prevents the government from evading accountability and making an end-run around the courts by attempting to execute prisoners under a protocol that has never been authorised by Congress,” said the convicts’ attorney, Shawn Nolan. “The court has made clear that no execution should go forward while there are still so many unanswered questions about the government’s newly announced execution method.”

The death penalty remains legal in 30 states, but only a handful regularly conduct executions. Texas has executed 108 prisoners since 2010, far more than any other state.

Though there hasn’t been a federal execution since 2003, the Justice Department has continued to approve death penalty prosecutions, and federal courts have sentenced defendants to death.