Tennessee prison officials are asking a judge not to force them to reveal the supplier of their lethal injection drugs ... TMZ has learned.

An unidentified official from the Tennessee Department of Correction filed a declaration in Christa Pike’s court battle over her botched execution.

The official claims to be responsible for procuring pentobarbital for use in carrying out death sentences. According to the declaration, the state’s supplier has made it clear … if the government reveals who the supplier is ... they will no longer supply it to the state.

The anonymous official says, “I am aware of suppliers’ concerns that disclosure of their identities will result in harassment, retaliation and retribution against the suppliers and/or the suppliers' employees."

The move comes a month after Christa demanded the prison officials preserve evidence related to her failed execution on September 30. She also complained about being in solitary confinement and has since asked to move to general population.

As TMZ previously reported, Christa was sentenced to death for the 1995 murder of Colleen Sleemer. She was given two doses of pentobarbital but did not die. She was hospitalized for nearly two weeks before being sent back to prison.