OTTAWA - A sophisticated Conservative effort to cyber-scour the backgrounds of anyone attending Stephen Harper's rallies triggered pointed exchanges Tuesday about "un-Canadian" campaign tactics.

Liberal Leader Michael Ignatieff fired the first salvo after two young women were brusquely booted out of a Conservative event in London, Ont., on the weekend.

Awish Aslam reportedly broke into tears after she and her friend were escorted out of the Harper rally and had their name tags ripped off and torn up.

The reason? Their Facebook pages featured a photo of the pair posing with Ignatieff at a recent Liberal event.

The Liberal leader pounced.

"When you get to a situation where people can't come to a public meeting in Canada, and get thrown out by two heavies because they have a Facebook friend from another party, you're in a bad place," Ignatieff said at his first campaign stop Tuesday morning. UBC Writing Centre- More courses begin in March.

"You’re in a very un-Canadian place.”

Initially, Harper tried to brush the issue aside, laying the blame at the feet of his campaign workers.

"Staff runs our campaigns and I can't comment on individual matters like that," he said during a campaign stop in Quebec.

But as the issue gathered media momentum throughout the day, Harper spokesman Dimitri Soudas said he would seek out the woman and apologize.

Soudas denied that the party does background checks on its audience.

Tory cabinet minister John Baird summoned the media in Ottawa to fire his own charges of un-Canadian behaviour back at Ignatieff, whose long been portrayed by the Conservatives as "just visiting" Canada.

Baird defended the party's practice of screening attendees at its campaign events, citing it as necessary given space constraints at most venues.

"If a party's going to have a political rally, a rally of Conservatives, and we have thousands of Conservative members in that area, there's not room for everyone, obviously," he said.

"We have to manage how many people can attend."

Ignatieff, he said, "is a man who has called the United States his country, a man who has called the Canadian maple leaf a pale imitation of a beer label.

"He should be the last person to call anyone un-Canadian."

The London incident wasn't the only complaint to surface about people being excluded from Harper's campaign events.

The Halifax Chronicle-Herald reported that a volunteer who helps homeless veterans was turned away from a news conference with Harper in Halifax last week.

And another student posted on his Facebook page that he and a handful of others were ushered out of a Guelph, Ont. event last week.

NDP Leader Jack Layton also set his sights on Harper.

"This is a prime minister who wants to control everything," Layton said.

He cited the controversy raging about former Harper adviser Bruce Carson, who was appointed to a key job in the Prime Minister's Office despite having been convicted of fraud.

"He doesn't want someone who disagrees with his policies to be even in the same room, but it's OK for someone to be convicted of fraud to not only be close to the prime minister but to work with him in the PMO."

Harper has acknowledged knowing that Carson had been convicted in one case involving two counts of fraud, but not in another case involving three.

Layton said he doesn't believe Harper, and he claimed most Canadians don't either.

"This is just more proof that Stephen Harper can't be trusted.”

Both opposition leaders took pains to explain that they are willing to meet Canadians of all political stripes during the campaign, and that there is no litmus test for admission to their rallies.

Layton's campaign even distributed a photo of Aslam attending a NDP rally that took place earlier the same day she was kicked out of the Conservative event.

Harper leader's tour has been dubbed the "bubble-boy campaign" by Ignatieff and been criticized by even some Tories.

Reporters following the prime minister have written about limited access: they're restricted to five questions a day. Individuals attending events must register and show identification, and rarely do events stray into public places where access isn't strictly controlled.

RCMP officers on the tour make a point of telling reporters at events that they are not acting as prime ministerial staff, and if they yank a reporter aside, it is for security reasons only.

Last week, a Conservative staffer called the tactic "stupidity" in a Facebook entry that was leaked to the media, and pleaded with the party war room to save Harper's "image."

At Tory rally Tuesday night in Quebec, Tory incumbent Maxime Bernier insisted that the Conservative party is open to fresh faces and new ideas.

There are no restrictions on his campaign events, he added.

"It's all open for people — in my riding, everyone can come," Bernier said. Members of the public can also engage through the media, on the Internet and via social networking.

"I think we are an open party, and we like to debate and the best one will win. What is an election right now if it is not about debates?"

-Julian Beltrame reports for the Canadian Press.