Execution of US murderer Christa Pike halted shortly before it was due to happen

The execution of Tennessee inmate Christa Pike has been halted just over 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.

"We will continue to advocate for the lawfully imposed sentence as the courts work through this technical issue," Tennessee's Attorney General said in a statement.

"It is common in capital cases for the defence to raise last minute objections following decades of litigation in numerous courts. We are asking the Supreme Court of the United States to lift the stay."

She was 18 when she and her then-boyfriend, Tadaryl Shipp, 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.

A year later, Pike was sentenced to death, while Shipp - who was 17 at the time - was given a life sentence with the possibility of parole.

Pike has a documented history of childhood sexual abuse, abandonment and neglect. Her lawyers believe that if she was found guilty of the same crime today as a teenager she would not receive a death sentence.

Last year, Tennessee's Supreme Court ruled Pike had not shown circumstances that would justify commuting her sentence.

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