An Oklahoma Department of Corrections spokesman says an inmate's execution has been canceled following a stay order from the state Supreme Court.

Clayton Lockett was scheduled to die by lethal injection for the 1999 shooting death of 19-year-old Stephanie Nieman. But corrections spokesman Jerry Massie says Monday's stay order put the punishment on hold.

The stay also canceled the scheduled April 29 execution of inmate Charles Warner, who was convicted in the 1997 death of his roommate's 11-month-old daughter.

The stay halted the executions until the state Supreme Court can hold a hearing on the inmates' lawsuit challenging the secrecy protocol surrounding the source of Oklahoma's lethal injection drugs. A hearing date has not been set.

Attorney General Scott Pruitt's office is asking the court to reconsider its ruling.