Rachelle Renae Shannon, 37, was accused of shooting George Tiller, one of the few American physicians who perform late-term abortions and long the target of protests from anti-abortionists.
Police said four or five shots were fired at Dr Tiller after he left his clinic in Wichita, Kansas, on Thursday and climbed into his van. He was slightly wounded in each arm but was later released from hospital, vowing to continue carrying out abortions.
The shooting was the latest attack in an increasingly nasty battle over abortion in the US which has led to death threats and acid attacks on clinic staff, and has caused some physicians to carry guns to work. Dr Tiller, 52, sometimes wore a bullet- proof vest and travelled with a guard dog - although it appears he was using neither form of protection when he was shot.
The abortion feud claimed its first fatality in March when Dr David Gunn, 47, was shot dead outside a clinic in Florida during an anti-abortion demonstration sponsored by Rescue America, a group known for its extreme views. Michael Griffin, an outspoken 'pro-lifer', was heard to shout 'Don't kill any more babies' as he fired three shots into Gunn's back. He later gave himself up to police. Witnesses said other demonstrators appeared pleased by the killing.
The founder of Rescue America, Don Treshman, set up a fund for Mr Griffin's family. After Gunn's death, Mr Treshman issued a statement that heightened the fury of pro-abortionists. 'This shooting, while unfortunate, will result in babies' lives being saved,' he said.
After Thursday's attack on Dr Tiller, Mr Treshman said that the shooting may be 'a blessing in disguise for Tiller . . . God may be giving him another chance to realise the horror of what he is doing.' But Operation Rescue, another prominent 'pro-life' group, distanced itself from the incident, saying it did not support 'vigilante acts of violence'.
Planned Parenthood, the pro-abortion group, described the shooting as 'a breakdown of law and order' in America. 'It is a national disgrace, and it must be stopped. We call on every American to express outrage at these troubled, frenzied zealots who think they can take the law into their own hands.'
Ms Shannon was arrested at Will Rogers Airport in Oklahoma City after returning a rental car that police said matched one seen leaving Dr Tiller's clinic after the shooting. Witnesses said the assailant had joined a small demonstration outside the clinic, handing out literature and speaking to the protesters. After the shooting, clinic employees chased the woman, but she escaped.
Dr Tiller's clinic was one of three picketed by Operation Rescue two years ago, a widely publicised operation that led to 2,700 arrests.
Last week, a Roman Catholic priest in Alabama sought to run an advertisement in a newspaper advocating killing doctors who perform abortions, calling it 'justified homicide'. The newspaper refused to run the advertisement, while church officials ordered the priest, the Rev David Trosch, to recant or resign. His publicity stunt came shortly after a US visit by Pope John Paul II, who confirmed his opposition to abortion several times during his trip.