COLORADO SPRINGS, Colo. - The man who police say stormed a Planned Parenthood clinic, killing a police officer and two others, used the phrase "no more baby parts" to explain his act, according to a law enforcement official.

Robert Lewis Dear's attack on the clinic was "definitely politically motivated," said the official, speaking on the condition of anonymity because the investigation is still underway. NBC News, which first reported the comment, said Dear also mentioned President Obama in a range of statements to investigators that left his precise motivation unclear.

Yet even as authorities released few details about Friday's shootings, the politics of the highly charged abortion issue seemed to outstrip their efforts to be methodical. While antiabortion activists denied any knowledge of Dear and said he is not affiliated with their movement, abortion-rights activists countered that comments by conservatives against Planned Parenthood had precipitated the violence.

Vicki Cowart, president of Planned Parenthood of the Rocky Mountains, cited "eyewitness accounts" in asserting that Dear "was motivated by opposition to safe and legal abortion."

"We've seen an alarming increase in hateful rhetoric and smear campaigns against abortion providers and patients over the last few months," she said in a statement. "That environment breeds acts of violence."

Planned Parenthood, which provides abortions and other health-care services, has been at the center of a political storm as the 2016 presidential campaign heats up. Republican candidates have denounced the organization, especially after an antiabortion group released a series of surreptitiously filmed videos in which Planned Parenthood officials discussed the techniques and financial aspects of harvesting fetal-tissue samples for scientific research.

It was at the Colorado Springs Planned Parenthood clinic where Dear, 57, is accused of fatally shooting University of Colorado Police Officer Garrett Swasey and two as-yet unnamed civilians. At least four other officers and five civilians were also injured. Officials said Saturday that the injured victims were expected to recover.

Dear, who moved to Colorado last year, was described by people who know him as a malcontent and drifter who has had numerous run-ins with the law. He is being held without bond and is scheduled to appear in court Monday, local media reported.

He is expected to face state charges and then federal charges, said the law enforcement official. It was unclear whether an attorney had been appointed.

On Saturday, witnesses described scenes of chaos and carnage as gunshots began on a traditionally quiet day of post-Thanksgiving relaxation, with police responding to a call for help from the clinic, in a bustling area near a shopping center, medical building, grocery store, and restaurants.

A burst of gunfire early on gave way to relative calm, but witnesses said gunfire then started again. Many workers and shoppers were told to hunker down in place. Some remained in buildings or cars for hours as snow accumulated and the sky darkened.

Obama, in his first reaction to the shootings, issued a refrain for more gun-control measures, which has become a depressingly familiar ritual after mass shootings. But unlike after other incidents, he limited his remarks to a written statement. Regardless of the motive, he said, the frequency of mass killings in the United States is unacceptable.

"This is not normal. We can't let it become normal," the president said. "If we truly care about this . . . then we have to do something about the easy accessibility of weapons of war on our streets to people who have no business wielding them. Period. Enough is enough."

At a vigil Saturday at All Souls Unitarian Church, the Rev. Nori Rost called the gunman a "domestic terrorist." In the back of the room, someone held a sign that said: "Women's bodies are not battlefields. Neither is our town."

Cowart drew a standing ovation when she walked to the pulpit. She promised to quickly reopen the clinic. "We will adapt. We will square our shoulders and we will go on," she said.

After her remarks, a woman in the audience stood up, objected to the vigil's becoming a "political statement," and left.

On the Republican campaign trail, candidates who have been full-throated in their denunciations of Planned Parenthood fell nearly silent. Only Sen. Ted Cruz and Ohio Gov. John Kasich referred to the shootings, but neither mentioned Planned Parenthood.

All three leading Democratic candidates issued statements supporting Planned Parenthood, and they were joined by others in the abortion-rights community who condemned the criticism of the organization.

Antiabortion groups were quick to denounce the shooting and distance themselves from Dear, with numerous activists saying they have never interacted with or heard of him.

This article contains information from the Associated Press.