US president Barack Obama has said he is shocked and outraged at the murder of a top doctor who performed late-term abortions.
Dr George Tiller, the object of decades of protests and attacks, was shot dead in front of his wife in a Kansas church where he was serving as an usher.
A 51-year-old man was arrested 170 miles away in Kansas City three hours after the shooting on Sunday.
Johnson County sheriff's spokesman Tom Erickson identified the suspect as Scott Roeder. There was no immediate word of the killer's motive, but the doctor's violent death was the latest in a string of shootings and bombings over 20 years directed against abortion clinics, doctors and staff.
In a statement issued by the White House, Mr Obama said: "However profound our differences as Americans over difficult issues such as abortion, they cannot be resolved by heinous acts of violence."
Long a focus of national anti-abortion groups, including a summer-long protest in 1991, Dr Tiller, 67, was shot in the foyer of a Reformation Lutheran Church.
His lawyer, Dan Monnat, said Dr Tiller's wife Jeanne was in the choir at the time.
The killing was "an unspeakable tragedy", his widow, four children and 10 grandchildren said in a statement. "This is particularly heart-wrenching because George was shot down in his house of worship, a place of peace," it said.
The family said its loss "is also a loss for the city of Wichita and women across America. George dedicated his life to providing women with high-quality health care despite frequent threats and violence".
Mr Stolz said all indications were that the gunman acted alone, although authorities were investigating whether he had any connection to anti-abortion groups.
