TORONTO -- Liberal Leader Justin Trudeau wore a bulletproof vest amid heavy security presence Saturday as he appeared 90 minutes late to a campaign rally due to unspecified security concern.

Trudeau, who is known to wear rolled-up shirtsleeves during speeches, wore a blue suit jacket on stage that visibly bulged from the protective gear underneath.

His wife, Sophie Grégoire Trudeau, was scheduled to introduce him at the Mississauga, Ont. event, but did not appear on stage.

The intense security detail was unusual for a campaign rally, reported CTV’s Glen McGregor, who has been following the Liberal campaign.

The Liberal Party would not comment on the security concern.

NDP Leader Jagmeet Singh and Conservative Leader Andrew Scheer both expressed their concerns about the incident on Saturday.

“Any threat made against @JustinTrudeau, or any leader, is troubling to all of us. No matter how you vote or believe, no one should face threats of violence. To the officers who protect all of us – thank you,” Singh tweeted.

Scheer tweeted it was “very upsetting” to hear that Trudeau had to wear a bulletproof vest at a campaign event.

“Threats of violence against political leaders have absolutely no place in our democracy. Thank you to the RCMP for taking these threats seriously and keeping us safe,” he posted.

Trudeau met with an estimated 2,000 supporters in the Ontario riding as he hopes to motivate supporters to head to the polls. It was the biggest crowd of his campaign so far.

In his address, Trudeau tried to convince left-leaning voters to support the Liberals rather than the NDP after recent polls showed a spike in support for Singh’s party.

"If you want progressive action, you need a progressive government, not a progressive opposition," Trudeau said.

The election will be held on Monday, Oct. 21. Early voting has already begun across the country.