Republican presidential front-runner Donald Trump is refusing to blame Friday's deadly shooting, which killed three people at a Planned Parenthood facility in Colorado Springs, on anti-abortion sentiment.

Instead, the real estate mogul attributes the attack on the clinic to mental illness.

"I think it's a terrible thing. And he's a maniac," he told NBC Sunday. "I think he's a sick person and I think he was a -- probably a person ready to go. We don't even know the purpose -- I mean he hasn't come out to the best of my knowledge with a statement as to why it happened to be at that location."

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"This was an extremist and this was a man who obviously -- and they said prior to this that he was mentally disturbed so he's a mentally disturbed person -- there's no question about that," he continued.

The billionaire admitted, however, that there is "tremendous dislike" for Planned Parenthood among conservatives, bolstered by undercover videos released in July that showed top clinic officials discussing fetal body parts for research purposes.

"There is a tremendous group of people that think it's terrible all of the videos that they've seen with some of these people from Planned Parenthood talking about it like you're selling parts to a car," Trump said. "There are a lot of people that are very unhappy about that."

While the motives of the shooter, 57-year-old Robert Lewis Dear, have yet to be revealed, a law enforcement official said that Dear uttered the phrase "no more baby parts" after he was arrested. In September, the FBI also issued an intelligence bulletin warning against possible "lone offender" attacks on Planned Parenthood facilities as the nationwide debate to defund the organization ramped up.

On Sunday, Planned Parenthood officials also linked the attack on the facility to the "negative environment" created by the anti-abortion critics of Planned Parenthood services.

In a press release, Dawn Laguens, executive vice president of Planned Parenthood Federation of America, said: "It is offensive and outrageous that some politicians are now claiming this tragedy has nothing to do with the toxic environment they helped create. Even when the gunman was still inside of our health center, politicians who have long opposed safe and legal abortion were on television pushing their campaign to defund Planned Parenthood and invoking the discredited video smear campaign that reportedly fed this shooter's rage."

Democratic presidential candidate Bernie Sanders repeated similar sentiments on Saturday, when he said in a statement, "Planned Parenthood has been the subject of vicious and unsubstantiated statements attacking an organization that provides critical health care for millions of Americans."

Former Hewlett-Packard executive and Republican presidential contender Fiorina fired back at the conservative blame, calling such rhetoric "typical" of liberal propagandists.

"What I would say to anyone who tries to link this terrible tragedy to anyone who opposes abortion or opposes the sale of body parts is, this is typical left-wing tactics," she said in an interview with Fox News Sunday. Fiorina, who was a leading proponent of stripping away federal funds for the women's health clinic earlier this year, didn't shy away from continuing her own criticisms of the embattled organization saying that "the vast majority of Americans agree, what Planned Parenthood is doing is wrong."

Texas Sen. Ted Cruz also warned against assigning motive to the tragedy prematurely.

"I think there has been some vicious rhetoric on the left blaming those who are pro-life," Cruz said in Iowa Sunday. " It was a multiple murder of what appears to be a deranged individual and it was horrific, it was evil, and we will find out more about the facts but I don't think we should jump to conclusions."

Former Arkansas Gov. Mike Huckabee echoed the denunciation of tying GOP rhetoric to the Colorado attack, telling CNN that "it's a little bit disingenuous on the part of Planned Parenthood to blame people who have a strong philosophical disagreement with the dismembering of human babies and with the selling of body parts to say that we would like to retaliate by sending some madman into a clinic to kill people."

"God knows that's not what anybody would want," Huckabee said Sunday. "And this person, apparently, from everything we know, very unstable person, and just a terrible tragedy, especially for that police officer and his family."

The Republican contender did acknowledge that the shooting was an act of "domestic terrorism," and that the actions of the gunman were "absolutely abominable, especially to those of us in the pro-life movement, because there's nothing about any of us that would condone or in any way look the other way at something like this."