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       A fundraising letter received in the mail from the Ontario Progressive Conservative party in North Bay, Ont.

       Veronica Doyon/The Canadian Press

       Ontario’s Progressive Conservatives are apologizing for sending a letter to supporters that asked for donations on a form that resembled an invoice.

       The party says in a statement this morning that the correspondence was sent to a “limited group of supporters” by a vendor.

       The Tories say they didn’t intend to mislead people and that they regret the correspondence.

       It’s the first time the party has acknowledged that it was responsible for the letters, images of which began circulating on social media earlier this week.

       Opposition parties have called for investigations, including a police probe, into the letters, which the Liberals argue could constitute a scam.

       The Liberals have also called for the Progressive Conservative party to return any funds it received from people through the mailouts.

       A photo of the letter one of the recipients shared with The Canadian Press displays the word invoice across the top, with the phrase “please pay today.”

       It shows a “balance due” of $300 for what’s described as an “election readiness fund.” The document describes the payment as a donation in smaller text lower down on the page.

       Premier Doug Ford has not commented on the letters, but Toronto radio host Jerry Agar says Ford called him to say he was “angry” about the correspondence.