Oklahoma's attorney general says the state does not have all of the lethal drugs necessary to carry out an execution set for Thursday.
Two inmates, scheduled to die this month, have been fighting their executions while they seek more information about Oklahoma's execution procedures.
Despite the drug shortage, state lawyers are still fighting their request in court.
State leaders say they are trying to get the execution drugs and will change protocols if necessary to execute Clayton Lockett this Thursday night at 6:00.
The attorney general's office said in briefs filed with the Oklahoma Court of Criminal Appeals on Monday that a deal to obtain pentobarbital and vecuronium bromide from a pharmacy had fallen through.
Pentobarbital is a sedative; vecuronium bromide is a muscle relaxant.
A third drug stops the heart.
Charles Warner is to die March 27.