WASHINGTON, United States (AFP) — A Tennessee woman convicted of murder survived two lethal injection doses and was hospitalised on Thursday, her lawyers said, marking the state’s second failed execution in months and prompting it to halt capital punishment this year.

Hours earlier on Wednesday the Supreme Court cleared the way for Christa Pike, 50, to become the first woman to be executed in the southern US state of Tennessee in 200 years — but the attempt failed.

“This event is the worst we’ve seen and unlike any other botched execution in the modern era,” Robin Maher, the executive director of the Death Penalty Information Center, told the New York Times. “There is no precedent.”

The Tennessee Department of Correction said that it “followed every step of the state’s lawful, established execution protocol”, adding that Pike was subsequently taken to an “off-site medical facility”.

Her attorneys said she was transported to a nearby hospital, adding they have not been informed as to her condition.

“Tonight the State of Tennessee once again failed to carry out a lawful execution,” the attorneys said in a statement.

Tennessee halted the execution by lethal injection of Tony Carruthers in May after medical staff were unable to tap a vein.

Governor Bill Lee called for a “comprehensive, third-party review” after Pike’s failed execution.

“The remaining scheduled execution will not be carried out this year,” Lee said — apparently referencing the execution of convicted killer Gary Wayne Sutton scheduled for December 3.

Pike was scheduled for execution at 10:00 am (1500 GMT) at the Riverbend Maximum Security Institution, where witnesses including journalists were present for the administration of the injections.

Kim Chandler, a media witness with Associated Press, told CBS News that, “Pike appeared notably awake as the execution began.”

After the blinds of the execution chamber closed for the final time, Pike “could be heard loudly snoring, clearly very alive in the chamber until media witnesses were told to leave the area”, Chandler said.

During a livestream, an ambulance with its lights flashing could be seen leaving the site of the execution. It was unclear if it was transporting Pike.

The execution procedure went ahead hours after the US Supreme Court ruled that it could proceed, with liberal justices Sonia Sotomayor, Elena Kagan and Ketanji Brown Jackson all dissenting.

“The court’s decision… unnecessarily prevents that (lower) court from giving due consideration to Pike’s claim,” the dissenting justices wrote.

“Worse, the court grants such extraordinary relief solely to allow the state to execute Pike before litigation over her conviction has properly run its course in the lower courts.”

The case has sparked debate over capital punishment for young criminals.

Pike was 18 when she and her boyfriend beat and killed Colleen Slemmer, 19, at a job training camp for young people.

The killing gained national attention after Slemmer’s body was found with a pentagram, often seen as a satanic symbol, carved in her chest.

Pike’s lawyers argued she should be granted clemency due to her young age and mental health issues at the time of the killing.

“She was 18 when she committed her crime, and she was deeply mentally ill,” they wrote in a clemency petition to Tennessee Governor Bill Lee, who said he would not intervene.

The US Supreme Court had rejected Tuesday an application for a stay of execution, which argued that Pike’s history as a victim of sexual assault, post-traumatic stress disorder and a blood condition meant a lethal injection would cause “needless suffering”.

Independent UN rights experts have urged the US government and Tennessee authorities to “immediately halt” the execution and commute her death sentence.

In the United States, only 18 women have been executed since 1976, according to the Death Penalty Information Center.