In this March 2009 photo, Dr. George Tiller answers questions after being called to the witness stand in Sedgwick County District Court in Wichita, Kan. (Mike Hutmacher/Associated Press)

Dr. George Tiller, one of the few providers of late-term abortions in the United States, was shot and killed Sunday in a Kansas church where he was serving as an usher.

The gunman fled, but a 51-year-old suspect was arrested about 275 kilometres away in suburban Kansas City three hours after the shooting, Wichita Deputy Police Chief Tom Stolz said.

The suspect's name was not released. Police had been looking for a gunman who fled in a car registered in the Kansas City suburb of Merriam.

Stolz said all indications were that the shooter acted alone, although authorities were investigating whether he had any connection to anti-abortion groups.

Stolz said the suspect was being brought back to Wichita, where he would likely be charged Monday with one count of murder and two of aggravated assault. Stolz said the gunman threatened two people who tried to stop him.

There was no immediate word on the possible motive of Tiller's assailant.

But the doctor's violent death was the latest in a string of shootings and bombings over two decades directed against abortion clinics, doctors and staff.

Tiller's wife in choir

Long a focus of national anti-abortion groups, including a summer-long protest in 1991, Tiller was shot in the foyer of Reformation Lutheran Church, Stolz said. Tiller's lawyer, Dan Monnat, said Tiller's wife, Jeanne, was in the choir at the time.

The slaying of the 67-year-old doctor is "an unspeakable tragedy," his widow, four children and 10 grandchildren said in a release. "This is particularly heart-wrenching because George was shot down in his house of worship, a place of peace."

Tiller's Women's Health Care Services clinic is one of just three in the United States where abortions are performed after the 21st week of pregnancy. The clinic was heavily fortified and Tiller often travelled with a bodyguard, but Stolz said there was no indication of security at the church Sunday.

Anti-abortion groups denounced the shooting and stressed that they support only nonviolent protest.

"We are shocked at this morning's disturbing news that Mr. Tiller was gunned down," Troy Newman, Operation Rescue's president, said in a statement. "Operation Rescue has worked for years through peaceful, legal means, and through the proper channels to see him brought to justice.

"We denounce vigilantism and the cowardly act that took place this morning."

Service continued

At the church, Adam Watkins, 20, said he was sitting in the middle of the congregation when he heard a small pop at the start of the service.

"We just thought a child had come in with a balloon and it had popped, had gone up and hit the ceiling and popped," Watkins said.

Another usher came in and told the congregation to remain seated, then escorted Tiller's wife out. "When she got to the back doors, we heard her scream, and so we knew something bad had happened," Watkins said.

He said the service continued after an associate pastor announced that Tiller had been injured.

"We were just really shocked," he said. "We were kind of dumbfounded. We couldn't really believe it had happened."

Tiller had in the past endured threats and violence. A protester shot Tiller in both arms in 1993 and his clinic was bombed in 1985.

More recently, Monnat said Tiller had asked federal prosecutors to step up investigations of vandalism and other threats against the clinic out of fear that the incidents were increasing and that Tiller's safety was in jeopardy.

Stolz, however, said police knew of no threats connected to the shooting.