A new Conservative attack ad takes aim at Liberal Leader Justin Trudeauā€™s position on the mission against the Islamic State, but it uses the terrorist groupā€™s own horrifying propaganda images.

In the online ad, posted on the Conservative Partyā€™s , Trudeau is shown in a CBC interview saying he would end the CF-18 bombing campaign against the terrorist group, also known as ISIS or ISIL.

The ad uses Islamic State propaganda, including gruesome images of prisoners facing death by drowning and beheading -- and those images may actually violate the governmentā€™s own anti-terror law.

The new C-51 legislation gives a judge ā€œthe power to order the seizure of terrorist propaganda or, if the propaganda is in electronic form, to order the deletion of the propaganda from a computer system.ā€

ā€œHere they are using the music and images of a terrorist organization. So not only does it undermine decency, but it undermines the credibility of the Conservatives on their own bill,ā€ NDP MP Paul Dewar told Ā鶹“«Ć½.

Advertising executive Tony Chapman wondered how the uses of ISIS imagery would help the Conservatives score political points.

ā€œNot only are they providing free advertising for ISIS, theyā€™re completely offside and driving Canadian politics to a new low,ā€ said Tony Chapman.

Meanwhile, Prime Minister Stephen Harper continued the political attack Thursday during remarks to reporters in Quebec City.

Harper suggested Trudeau would cut relations with Canadaā€™s coalition allies in the fight against Islamic State in Syria and Iraq. He also accused Trudeau of wanting to ā€œbecome best friendsā€ with Iran, ā€œone of the state sponsors of terrorism in the world.ā€

He then slammed Trudeau and NDP Leader Tom Mulcair for ā€œirresponsible electoral politicsā€ in their positions on the anti-ISIS mission.

The federal NDP made huge strides in Quebec in the last federal election, picking up 58 of the provinceā€™s 75 seats to help them reach a total of 95 seats in the House of Commons.

Mulcair has already stated that he would pull Canadian troops out of Iraq if he becomes prime minister. He said last March the NDP would be open to Canada participating in a UN or NATO mission, but not ā€œan American-led mission.ā€

Harperā€™s comments about Trudeau come days after the Liberal leader said he would halt Canadaā€™s bombing missions against ISIS in favour of sending military personnel over to train local troops on the ground.

On Thursday, Trudeau reiterated his position.

ā€œWe just donā€™t necessarily do it in the way Mr. Harper doing by dropping bombs; thereā€™s much we can do around training and humanitarian support,ā€ he said.

Trudeau has also said he would explore re-opening relations with Iran. In 2012, Canada suspended diplomatic relations with Iran and closed its embassies in that country.

With a report from CTVā€™s Richard Madan