Conservative Leader Stephen Harper didn't like the headline, but he isn't backing down from the substance of a party news release attacking Paul Martin and the Liberals on child pornography.

"I'm not going to, in any way, give the Liberal Party any break in its record on child pornography," Harper told reporters at a campaign stop in Drummondville, Que. Friday. "It is disgraceful, they have had multiple opportunities to do something about it, and they have refused."

Asked about the 'taste' of the headline, Harper said: "What's in bad taste is the Liberal Party's record on child pornography.

" I will not make excuses on it, I will attack them on it, and if (the Liberals) want to fight the rest of the election on it, good luck to them," he heatedly said before stepping back on his campaign bus.

Later Friday, Martin told reporters in Etobicoke, Ont.: "Look, this is personal. I am a father and I am a husband, and he has crossed the line. He should apologize."

Tim Murphy, the prime minister's chief of staff, said: "It's not so much about politics; it's about right and wrong. You would have thought that someone in an organization that has dozens if not hundreds of people, someone would have said, 'this is wrong. This went too far, this crosses the line'."

The campaign took on the a bizarre and ugly tone after the Conservative camp accused, then hastily withdrew, the suggestion that Liberal Leader Paul Martin was in favour of child pornography.

The attack -- which Martin refused to react to -- and the retraction represented the first undisciplined act from Harper's Conservative headquarters after what had been a very professional  campaign.

A Conservative press release bearing the headline "Paul Martin Supports Child Pornography?" was sent to media outlets across the country at 3:30 p.m. EDT Friday and recalled at 4:35 p.m.

"Conservative Party would like to recall the message, "Paul Martin Supports Child Pornography?," the party said.

It then sent the initial accusatory release out again at 4:49 p.m., and recalled it again a few seconds later.

"Today, Martin says he's against child pornography. But his voting record proves otherwise," said the original.

The misstep recalls former Ontario premier Ernie Eves' campaign screw-up last fall, when his team sent out a release calling Ontario Liberal Leader, now Premier, Dalton McGuinty a "reptilian kitten eater." Eves refused to apologize. That remark was cited as a turning point in the campaign.

NDP attacked too

The Conservatives had put out another news release Friday with the headline: "The NDP Caucus Supports Child Pornography?"

That release, issued at 1:25 p.m. EDT, wasn't retracted.

It claimed while NDP Leader Jack Layton has taken positions against child pornography, some caucus members have voted against measures the Tories supported.

"The NDP countered by saying: "The NDP does not support child pornography. And it is hard to imagine a worse day to play politics with this issue."  

Child pornography made its way into the news following a high-profile murder case in Toronto on Thursday.

Michael Briere, 36, pleaded guilty to first-degree murder in the 2003 death of 10-year-old Holly Jones.

Briere admitted he had a long-term fantasy about sex with a young girl and had been looking at child pornography obtained over the Internet just moments before he went out looking for a victim.