WINNIPEG - An attack ad by Manitoba's Opposition Progressive Conservatives has been pulled from Global Television in a copyright dispute that one expert says is part of a growing battle between media outlets and political parties.

The ad criticizes severance packages the NDP government gave to seven advisers who parted ways with Premier Greg Selinger in the wake of a leadership crisis last year. The 30-second spot is based almost entirely on Global News footage of the premier walking away from two reporters who were asking him questions.

Global has stopped airing the ads and has sent a letter to the Tories, demanding the ad be removed from other television channels as well as online sites such as YouTube and Facebook.

"Our video was used in the ad without permission," Ron Waksman, director of editorial standards and practices for Global News, said in a written statement Monday.

"We have taken steps to remove this ad from our airwaves, which is consistent with our long-standing policy not to provide Global News content for use in any third-party political advertising."

The Tory caucus office referred questions to staff at the party's headquarters, who did not return repeated calls and messages Monday.

Michael Geist, an associate law professor at the University of Ottawa who specializes in copyright law, said the dispute is similar to one last summer between the CBC and the Conservative Party of Canada over snippets of video used in an attack ad on Liberal Leader Justin Trudeau.

CBC editor-in-chief Jennifer McGuire said at the time the broadcaster was intent on maintaining a clear distinction between journalists and political parties.

Geist said political parties, along with others, can use portions of broadcasts or news clippings under the fair dealing provision of the Copyright Act — much like news outlets can use snippets of video generated by others.

But he said there are rules and the Manitoba Tory ad is "problematic" because it does not attribute the footage to Global News. The Tory ad also blurs out a Global logo on a reporter's microphone.

"They haven't attributed. In fact, in anything, they've sought to de-attribute," Geist said.

"We're seeing a growing tension (regarding) some media outlets and the use of some of the video they produce for political purposes."

While the Tory ad has not aired on Global for several days, it remained available on the Tories' Facebook page and YouTube channel Monday.

News from © The Canadian Press, 2015