The execution of Tennessee inmate Christa Pike has been halted an hour before it was due to happen.

Pike, 50, has been awaiting execution since she was convicted and sentenced to death in 1996 for the murder of Colleen Slemmer.

In their ruling on Wednesday, judges from the Sixth Circuit Appeals court said they needed more time to consider the arguments in Pike's case. It is unclear how long the pause will last.

This latest ruling comes after the Supreme Court denied a reprieve and the Tennessee governor declined to grant Pike's request for clemency earlier this week.

Her lawyers said that for years, the state of Tennessee argued in court that Pike had lied about being sexually abused as a child.

But at a recent hearing about her execution method, the State said it does not dispute she suffered sexual abuse and rape.

Pike's legal team asked the appeals court to send her motion back to the district court, arguing that if the federal courts based their ruling on the state's earlier claim that she was lying, then the federal review was affected.

The appeal that led to Wednesday's stay is different from that made to the Supreme Court, which refused to hear Pike's appeal.

It came from her challenge to Tennessee's lethal injection method, which Pike's lawyers said could cause suffering beyond what is needed to carry out the death sentence - something the Constitution does not allow. The lawyers argued that Tennessee's procedures had denied Pike a fair chance to prove this.

She was 18 when she and her then-boyfriend beat, tortured and murdered Colleen Slemmer, a 19-year-old they met at a job training camp for troubled teens.

The murder created a media frenzy in Knoxville, Tennessee in 1995, when the teen was found with a pentagram - a symbol that is associated with satanic groups - carved into her chest. Pike has denied carving the pentagram herself.

She had accused Slemmer of insulting her and trying to steal her boyfriend. Two other residents at the camp later testified that Pike had bragged about the murder before and after and showed them a piece of Slemmer's skull.

Her attorneys have argued that "an 18-year-old brain is not an adult brain" and that Pike was too young at the time of the murder to be sentenced to death for it.

At the time of her incarceration, Pike was the youngest person on death row, according to the Tennessee Department of Corrections.