Tennessee has delayed the execution of Christa Pike after officials ran into problems preparing the lethal injection, according to reports. Pike is the first woman placed on the state’s death row.

Pike was convicted of the 1995 murder of a fellow student and has spent decades on death row. Her execution had been scheduled for this week.

Officials cited an extended delay in establishing intravenous access, a problem that has affected other executions in the United States. No new date has been set.

The delay has reignited debate over lethal injection in America. Pike’s lawyers have long argued the method is cruel, while the state says it will reset the process.

Pike was 18 at the time of the killing, making her one of the youngest women ever sent to death row in the US. Her case has drawn attention from anti-death-penalty campaigners for years.

The state has not said when it will try again.