A federal judge early Thursday halted the Justice Department's plans to execute a man convicted of raping and killing a Kansas 10-year-old, a day before the execution was set to take place.

The Associated Press reported that U.S. District Judge Tanya Chutkan ruled against the Justice Department, ruling that the federal government must obtain a prescription for the use of pentobarbital, the drug used to carry out a lethal injection. 

All of the federal government's executions in 2020 have been carried out using the drug as correctional authorities around the country have struggled for years to obtain drugs used for lethal injections.

“The court hereby enjoins Defendants from executing Keith Nelson until they have met the requirements of the FDCA [Federal Food, Drug, and Cosmetic Act],” Chutkan wrote, according to the AP.

Keith Dwayne Nelson, 45, was sentenced to death in 2002 for the kidnap, rape and murder of a 10-year-old girl and has sat on death row for nearly two decades as the federal government only recently resumed performing executions for the first time in nearly 20 years.

Federal attorneys have argued that pentobarbital should not be subject to the prescription requirement when used in lethal injections.

Thursday's ruling would likely put a major roadblock in the way of further federal executions, as medical boards around the country discourage physicians from participating in executions by lethal injection.

The Trump administration will reportedly appeal the ruling. Nelson's execution would have been the fifth this year since the Justice Department moved to resume executions; two more are currently set for September.