The only woman on death row in the US, Lisa Montgomery, has been executed.

After a last-minute stay of execution was lifted by the US Supreme Court, the 52-year-old was killed by lethal injection at a prison in Terre Haute, Indiana, the BBC reports.

Montgomery's case attracted widespread media attention after her lawyers argued against her execution on the grounds that she was mentally ill and had suffered abuse as a child.

Pictured below are anti-death-penalty protestors who attempted to save the 52-year-old's life.

Protestors. [[imagecaption|| Credit: PA Images]]

Montgomery was sentenced to death in 2007 after she strangled a pregnant woman to death in Missouri before cutting out and kidnapping her baby.

Her victim, Bobbie Jo Stinnett, 23, went on to bleed to death.

Montgomery is the first woman to be put to death by the US government in 67 years.

Witnesses report that Mongtomery's face mask was lifted at the execution, and she was asked if she had any last words, to which she replied "no".

The 52-year-old was pronounced dead at 01:31 (06:31 GMT).

As per the BBC, Montgomery's lawyer, Kelley Henry, said that everyone who had participated in the execution "should feel shame".

"The government stopped at nothing in its zeal to kill this damaged and delusional woman," she said in a statement. "Lisa Montgomery's execution was far from justice."

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The execution was postponed twice; first as a result of the ongoing pandemic and a second time by a judge, before it was cleared by a Supreme Court ruling to take place in the early hours of Wednesday (January 13).

Late on Monday evening, a judge halted the execution until a mental competency hearing had been held, with Montgomery's lawyers drawing attention to the fact that she was mentally unwell and had been born with brain damage.

Montgomery was physically and sexually abused by her father, the BBC reports, and family members revealed that she was trafficked by her mother, with her lawyers comparing what she endured to torture.

It was argued by her defense team that at the time of her crime, she was psychotic.

This view was supported by 41 current and former lawyers and human rights groups including the Inter-American Commission on Human Rights.

Only woman on US death row has been executed