The man accused of opening fire at a Planned Parenthood clinic in Colorado reportedly said "no more baby parts" while he was being arrested.
The reports by NBC News and other US media have fuelled speculation the attack was linked to a controversy around Planned Parenthood's role in delivering fetal tissue to medical researchers.
However, there has been no official word on what motivated the man who mounted the attack in which three people were killed.
The media reports cited unidentified law enforcement sources.
Planned Parenthood have vowed to quickly reopen the Colorado Springs abortion clinic attacked by a gunman on Friday.
Three people were killed in the attack including police officer Garrett Swasey. Nine others were injured when the gunman, named as Robert Dear, open fired at the clinic.
Vicki Cowart, regional director of the company, said they would learn from the attack and "square our shoulders" as she spoke at a vigil for the victims.
Cowart confirmed all 15 employees at the clinic survived and worked hard to get others in the building to safety.
She received a standing ovation as she walked up to the church pulpit to address the room. At the back, someone held a banner that read "Women's bodies are not battlefields. Neither is our town."
President Barack Obama said the US needs to crackdown on the "easy accessibility of weapons on our streets" after a shooting left three dead and nine injured at an abortion clinic in Colorado.
If we truly care about this - if we’re going to offer up our thoughts and prayers again, for God knows how many times, with a truly clean conscience - 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
Paying tribute to the police officer who was killed in the shooting, Obama added: "May God bless Officer Garrett Swasey and the Americans he tried to save."
Police have named the suspect behind a shooting at a Colorado Springs abortion clinic as 57-year-old Robert Dear.
Passengers forced to flee a BA plane that burst into flames on the runway at Las Vegas are taking legal action against the manufacturers.Read the full story ›
The police officer killed in a shooting at a Colorado Springs' abortion clinic has been named as Garrett Swasey, 44.
Mr Swansey was a campus police officer for the University of Colorado at Colorado Springs.
He joined city police in responding to the first reports of shots fired, authorities said.
Two civilians and a police officer were killed in the shooting at the Colorado Springs abortion clinic, officials have confirmed.
Police and the mayor of Colorado Springs, John Suthers, made the announcement at a news conference.
Nine other people - five police officers and four civilians - were injured in the incident.
The standoff at the clinic lasted about five-hours, before the gunman was arrested by police.
The gunman who opened fire at a Colorado Springs abortion clinic shot and killed a police officer, according to the Fraternal Order of Police, a law enforcement union.
Police later confirmed that an officer had been killed, but the exact number of fatalities in the shooting were unclear.
Immediately after the incident Lieutenant Catherine Buckley, a police spokeswoman, said she had no confirmation of fatalities
Later State Attorney General Cynthia Coffman posted a message on her official Twitter account saying two people had been killed, but that post was quickly deleted.
The shooting at an abortion clinic in Colorado Springs involved a "tragic loss of life", the Colorado attorney general tweeted.
The tweet appears to be the first indication there were fatalities in the incident.
An earlier tweet from the attorney general's office that referred to two people killed in the incident was deleted.
The standoff at the Colorado Springs abortion clinic "has been resolved", with the gunman taken into custody, officials at the scene have confirmed.
Mayor of Colorado Springs John Suthers told journalists the gunman was in custody.
"The situation has been resolved. There's no continuing peril to the citizens of Colorado Springs, but there is a huge crime scene that has to be processed," he said.
At least 11 people, including five police officers, are reported to have been injured. Officials would not confirm whether there had been any fatalities.