Warren Kinsella, the political strategist who until this week was actively working on Olivia Chow's mayoral bid, has taken legal action against John Tory adviser Nick Kouvalis, serving him with a notice of libel.

Mr. Kinsella, through his lawyer David Shiller, used Twitter to serve Mr. Kouvalis on Friday, linking to the libel notice through a Tweet. "We are the solicitors for Warren Kinsella. Please find attached our client's Notice of Libel," the tweet read.

The legal action is the latest escalation in a war of words between the Chow and Tory campaigns over the past week, which has included allegations of racism and "dirty politics."

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Mr. Kinsella's notice of defamation alleges that Mr. Kouvalis libelled him in a series of tweets on Thursday by writing that the Chow campaign "made a very smart move dumping Kinsella et al today.."

A separate tweet by Mr. Kouvalis reads, "@oliviachow to @kinsellawarren," before linking to the Irreplaceable music video by Beyoncé. The lyrics of that song include: "I can have another you by tomorrow/ So don't you ever for a second get to thinking you're irreplaceable."

According to the notice of libel, "The defamatory words meant or were understood to mean that: 1. Mr. Kinsella was fired by the Olivia Chow mayoral campaign; Mr. Kinsella was making a negative contribution to the Olivia Chow mayoral campaign; 3. The Olivia Chow mayoral campaign is better off without Mr. Kinsella; 4. Mr. Kinsella was shocked and/or surprised by Olivia Chow's alleged decision to fire him; and 5. Mr. Kinsella is easily replaceable by the Olivia Chow mayoral campaign."

Mr. Kinsella first sparked controversy last week, accusing Mr. Tory of "segregationist" policies on transit. He later apologized.

Since then, the Chow campaign has distanced itself from the strategist. Just this week, the campaign said Mr. Kinsella is no longer involved in its day-to-day operations.

Asked about Mr. Kinsella on Friday, Ms. Chow referred The Globe to her spokesman, Jamey Heath.

Mr. Heath said the Chow campaign has nothing to do with the online war of words. "I have no comment," he said.

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Asked if Mr. Kinsella had been fired from the campaign, he said: "Nothing that has been said by either Olivia's campaign or Mr. Kinsella supports that conclusion."

Mr. Kinsella himself declined to comment on Friday, referring questions to his lawyer. But on his website, he linked to Mr. Shiller's tweet in a post that read, "Hey Nick," and "You're served."

And in a post written earlier this week on dealing with online "trolls. The haters. The defamers. The stalkers," Mr. Kinsella gives the following advice: "Sue them. I have, plenty of times, and I've won plenty of apologies. … Suing someone in Small Claims Court, for real and meaningful defamation, is your legal right – and it's quite inexpensive and easy to do," he wrote. "Take my word for it: when you hit them in the pocketbook, they thereafter tend to be much more careful. Or they disappear."

Mr. Shiller said his firm chose to serve Mr. Kouvalis via Twitter because "we wanted to get it to his attention as quickly as possible."

He said Mr. Kinsella is asking for a retraction, a public apology and damages. He said his client wants the apology to be a public one, adding that "we would want the apology to be as public as the libel was. Twitter might be the place to do it, considering the defamatory comment was made on Twitter."

He was also careful to say the defendant in the case is Mr. Kouvalis alone, and not the entire Tory campaign.

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"He's doing this because a false statement has been made, and it's damaging to his reputation," he said. "It's as simple as that."

A spokesperson for the John Tory campaign declined to comment Friday. The campaign said Mr. Kouvalis – who was the mastermind behind Mayor Rob Ford's 2010 election campaign – would also not be commenting.

But on Twitter, just a half-hour after the tweet from @ShillersLLP was sent, Mr. Kouvalis tweeted yet another link to a music video – this one to the Johnny Cash song A Boy Named Sue.

With a report from Elizabeth Church.