Liberal Leader Justin Trudeau slammed the Conservatives Friday over media reports that suggested the Prime Minister's Office played a role in vetting Syrian refugees who had applied to resettle in Canada.

The Conservative government reportedly ordered a review of some cases this summer as a result of intelligence reports that warned that some Syrian refugees might pose a security threat.

A report by CTV News that cited unnamed sources said the PMO was discouraging the Department of Citizenship and Immigration from accepting Sunni or Shia Muslims and instead told it to focus on groups that the Conservatives had identified as particularly vulnerable to persecution, such as Arab Christians.

Trudeau accused the PMO of trying to select refugees that would better serve the government's political agenda, something he called "disgusting."

"We need to think about families who cross the ocean, desperately seeking to build a better life for themselves and for their kids," said Trudeau to an audience of supporters during a morning campaign stop in Toronto. 

"And to know that somewhere in the Prime Minister's Office staffers were poring through their personal files to try and see … which families would be suitable for a photo-op for the prime minister's re-election campaign. That's disgusting."

Trudeau vowed that a Liberal government would "absolutely not" prioritize religious and ethnic minorities.

Conservative Leader Stephen Harper said Thursday that the audit was ordered simply to ensure the most vulnerable individuals were being selected without compromising national security and insisted his staff members were not involved in the selection process.

Speaking at his platform launch in Surrey, B.C., on Friday, Harper said "vulnerable religious and ethnic minority groups in Iraq and Syria area are in fact being targeted by ISIS and its allies for extermination, and that is why we put a higher priority.

"It's not exclusionary, but obviously that is an important factor in making our refugee selections."

At his own platform launch event in Montreal, NDP Leader Tom Mulcair also criticized the Harper government for its decision to halt the processing of refugees while it ordered an audit. 

Stephen Harper is asked why his government prioritized certain types of Syria refugees2:19

​"Despite his emoting when we saw the lifeless body of that child... Mr. Harper and, in fact, his Prime Minister's Office were intervening to ensure that the neediest on Earth, those Syrian refugees, would not make it to Canada."

"This is the same Stephen Harper who's been playing the race card non-stop in this campaign," Mulcair said. "He's exploiting divisions among us."

Trudeau promises immediate middle-class tax cut

Trudeau was in the Conservative-held riding of Don Valley West in Toronto to announce that the first piece of legislation a Liberal government would introduce, should the party win the Oct. 19 vote, would be a tax cut for the middle class.

The proposed tax cut has been a central plank of the Liberal leader's election campaign. The cut would apply to Canadians making between $45,000 and $89,000 per year, and would save $670 per person each year, or as much as $1,300 for a two-income household, the party says.

Trudeau said the tax cut would be paid for by creating a new tax bracket of 33 per cent for those earning annual incomes of $200,000 or more.

Unlike Conservative tax cuts, he said, those eligible would see the money on their pay stubs right away, rather than having to wait for income tax season.

Tom Mulcair says Harper is playing the 'race card non stop in this campaign'1:14

He predicts that putting more money in the pockets of middle-class families would stimulate and grow the Canadian economy.

The Grit leader was surrounded by signs advertising the tax cut, as well as the plan for an increased child benefit for the families that Trudeau said need the money most.

The enhanced family benefit would be funded by eliminating the Conservatives' universal child care benefit for families making more than $200,000 per year in total income. 

He was also surrounded by piles of groceries — the amount of food, he said, a typical Canadian family would be able to purchase each month with the savings they would accumulate from the tax cut.

Justin Trudeau Liberal leader federal election 2015

Liberal Leader Justin Trudeau says the first thing his government would do, if elected, is cut taxes for the middle class. (Paul Chiasson/Canadian Press)

With files from The Canadian Press