Liberal Leader Justin Trudeau vowed he won't change how he campaigns despite being the target of an undefined threat that forced him to wear a bulletproof vest and beef up protective measures during a rally in Mississauga, Ont., on Saturday.

Speaking Sunday to reporters in Toronto, Trudeau refused to offer any specifics about the threat, saying only that his first concern was for the safety of his family and for all the Canadians at the Mississauga event.

"This will not change at all how I campaign, but I'm not going to make any further comments on it."

Trudeau's scheduled appearance at Saturday's rally, which attracted 2,000 supporters, was delayed by 90 minutes and featured a much heavier security detail once he took the stage.

Uniformed tactical officers wearing heavy backpacks surrounded Trudeau during his address. Trudeau's wife, Sophie Grégoire Trudeau, had been scheduled to introduce him, but she did not appear on stage. CBC News sources later confirmed the beefed-up security was a result of a security threat.

Trudeau was asked why they didn't just cancel the event for the safety of the 2,000 people if the security concerns were such that they prompted the cancellation of his wife's appearance and forced him to wear a protective vest.

Trudeau repeated his priority was the safety of his family and the people in the room.

"I took advice from the RCMP, worked with them," he said.

Trudeau also scolded the Conservatives for launching personal attacks leading up to the Oct. 21 vote, and spreading falsehoods and misinformation online about him that he said has also led to increased polarization and has affected people negatively.

But he did not directly blame the party for the threat against him.

In light of the threat, other party leaders put partisan politics aside to show support for Trudeau.

"Very upsetting to hear that Justin Trudeau had to wear a bulletproof vest tonight at a campaign event," the Conservative Leader Andrew Scheer tweeted Saturday night.

"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."

Very upsetting to hear that Justin Trudeau had to wear a bulletproof vest tonight 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. —@AndrewScheer

NDP Leader Jagmeet Singh also tweeted Saturday night that any threat against Trudeau or any other leader is "troubling to us all."

"No matter how you vote or believe, no one should face threats of violence," he tweeted. "To the officers who protect all of us — thank you."

Any threat made against <a href="https://twitter.com/JustinTrudeau?ref_src=twsrc%5Etfw">@JustinTrudeau</a>, 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. —@theJagmeetSingh

Speaking in Burnaby, B.C., Singh reiterated that he wanted to let Trudeau know he's sorry the Liberal leader had to ramp up security.

Singh said his team hasn't received any specific threats and "they're just doing their job to keep me safe."

Bloc Québécois Leader Yves-François Blanchet told reporters "there's absolutely no reason for any kind for violence," whether physical, verbal or threats through social media.

"If the authorities have judged that Mr. Trudeau required some more security, I can only agree with that."

But Blanchet did acknowledge he has received some kinds of threats, although nothing judged sufficient to require intervention by the authorities.

"I believe everybody has received that."

RCMP officials have told CBC News that when a political leader faces a serious security threat, the RCMP will complete a threat assessment. The leader's protective detail will then sit down with the leader to discuss how the RCMP would like to proceed. Together, all will then negotiate a plan.

If the leader still wants to attend an event despite the threat level being high, the RCMP would implement additional safety measures.

Last month, sources told CBC News the RCMP were compiling daily threat reports on online hate targeting federal political leaders during the campaign leading up to the Oct. 21 election, fearing it could spill over into real-world violence.

Meanwhile, there has been an increase in online posts condoning violence during the campaign, according to government sources close to the file.