Liberal Leader Justin Trudeau wore a bulletproof vest on stage amid heavy security at a campaign rally after a security threat, senior Liberal sources tell CBC News.

His appearance at a crowded rally of about 2,000 supporters in Mississauga, Ont., on Saturday evening was delayed by 90 minutes and featured a much heavier security detail around Trudeau once the Liberal leader took the stage.

Uniformed tactical officers wearing heavy backpacks surrounded the Liberal leader as he addressed the crowd. His wife, Sophie Grégoire Trudeau, was initially supposed to introduce him but did not appear on stage.

Trudeau delivered the speech without incident and shook hands with numerous supporters lining the stage and in the crowd as he left the venue.

When asked for more details, the Liberal Party said there would be no comment on Saturday night.

Heightened fears of violence

Saturday's extra security measures came amid heightened fears of violence on the campaign. Last month, sources told CBC News the RCMP were compiling daily threat reports on online hate targeting federal political leaders during the election campaign, fearing it could spill over into real-world violence.

Senior Liberal sources tell CBC, Justin Trudeau was wearing a bullet proof vest on stage for tonight’s rally, after a security threat. <br>He was delayed by 1.5 hours and much heavier security around him once on stage. Here’s what our cameras picked up. <a href="https://twitter.com/hashtag/cdnpoli?src=hash&ref_src=twsrc%5Etfw">#cdnpoli</a> <a href="https://twitter.com/hashtag/elxn43?src=hash&ref_src=twsrc%5Etfw">#elxn43</a> <a href="https://t.co/IZkRjO0bFl">pic.twitter.com/IZkRjO0bFl</a> —@salimah_shivji

Government sources close to the file confirmed an increase in online posts condoning violence during the campaign.

Just two weeks ago, Trudeau's security detail arrested a protester who approached the Liberal leader during the climate change strike march in Montreal.

In February, ahead of his testimony in front of the justice committee on the SNC-Lavalin affair, Michael Wernick, then-clerk of the Privy Council, warned of the dangers of rising hate on the campaign trail.

"I worry about the rising tides of incitements to violence when people use terms like 'treason' and 'traitor' in open discourse. Those are the words that lead to assassination," Wernick told committee members.