OTTAWA -- Party leaders kicked off the final two-week stretch of the 2021 federal election Tuesday with strong words in an effort to distinguish themselves from their opponents, while imploring for a respectful democratic campaign amid escalating violence from anti-vaccination protesters.

After Liberal Leader Justin Trudeau was hit but not injured by gravel thrown by protesters on his way out of a campaign stop in London, Ont. on Monday, the behaviour was roundly condemned across party lines.

Trudeau has increasingly sharpened his language in regards to these protesters, who have also ratcheted up their rhetoric and aggression against vaccines and any mandates to get them as the campaign has progressed.

From imploring these folks who have shouted obscenities and held signs evoking debunked conspiracy theories to 鈥減lease get vaccinated,鈥 to calling them 鈥渁nti-vaxxer mobs,鈥 the Liberal leader is now vowing he won鈥檛 be deterred by this 鈥渆ndangerment鈥 that he and others have faced by those who he described as 鈥減ractically foaming at the mouth鈥 in anger.

鈥淚 am staying focused not on me on this, but on how we make sure that everyone who isn't surrounded by security guards and well-wishers who have my back. Everyone who is walking into a hospital on their own for a late night shift, who's worried about some anti-vaxxer that might come scream at them and try to rip off their mask. Those are the people that I think about, those of the people I want to defend,鈥 he said during an announcement in Montreal.

鈥淭hey want to make their shouting and their aggression override democratic processes鈥 We will not let them win.鈥

Instead, Trudeau fixated his attacks Tuesday on his main opponent, Conservative Leader Erin O鈥橳oole. With the latest Nanos Research polling data showing the Liberals narrowly back in the lead ahead of the two potentially pivotal national leaders鈥 debates this Wednesday and Thursday, Trudeau made an effort to point out that O鈥橳oole has yet to present Canadians with the full costing of what he鈥檚 promising to do.

鈥淚 won鈥檛 call it a platform, because he actually hasn't costed it. There are no tables at the end of it like there are in the Liberal platform to show what the expenses are over the coming years, how much every promise will cost, and what the fiscal trajectory is, but he's going to magically get the budget back to balance? He's not showing his work, he's not doing his homework. And if you want to be taken seriously as a potential government, you have to be honest with Canadians,鈥 Trudeau said Tuesday.

鈥淏ut that's something that we're seeing is increasingly difficult for Mr. O'Toole to do. On guns, we've seen it very clearly, but it's in other ways鈥 I'm not going to believe whatever it is that he's trying to say at this particular minute, knowing that he might say something different an hour from now.鈥

O'TOOLE QUESTIONED ON PLATFORM COSTING

Responding to these comments and facing more questions Tuesday about when his platform鈥攚hich received an amendment in relation to his gun control policy over the weekend鈥攚ould be fully costed, O鈥橳oole couldn鈥檛 say when it would be available.

鈥淲hen we launched our plan we said we would have an update from the Parliamentary Budget Officer (PBO). We will have that I hope, shortly,鈥 O鈥橳oole said, dodging a question about why the party has not yet provided its own costing independent from the PBO鈥檚 work.

O鈥橳oole is not requiring all of his candidates to be vaccinated, and has suggested rapid testing as an alternative to allow unvaccinated Canadians access to spaces otherwise requiring proof of vaccination. He has largely been isolated from the kinds of angry protesters seen at Trudeau鈥檚 campaign stops.

Asked about this on Tuesday, O鈥橳oole said his decision to spend considerable time campaigning from a hotel studio in Ottawa is because of the pandemic and called the protesters鈥 behaviour seen at Liberal election stops 鈥渃ompletely unacceptable.鈥

鈥淲e should remember the country we are, which is a great democracy鈥 We need to have an election that reflects that. We're trying to run鈥 in a pandemic election鈥 as safe of a campaign as possible. That's why we use our studio to talk about our recovery plan, in-person, in the studio every day in a way that safe and positive,鈥 O鈥橳oole told reporters.

鈥淚 don't agree with Mr. Trudeau鈥檚 approach on many things, but I respect his ability to be able to communicate with Canadians free of harassment, intimidation, and violence.鈥

DON'T GET CAUGHT UP IN DESPAIR: SINGH

NDP Leader Jagmeet Singh also made clear his disagreement with Trudeau鈥檚 handling of key files鈥攕aying he鈥檚 been 鈥渁n abysmal failure鈥 on addressing the climate crisis鈥攚hile also condemning the protesters who threw the gravel.

鈥淚t is absolutely wrong to be throwing stones. I mean I can't imagine that I'm saying this in 2021: Don't throw stones at people because you disagree with them,鈥 Singh said at an event in Toronto, where he also sought to appeal to voters that the choice is between the Liberals and his party.

鈥淭he choice that we're putting to Canadians is: Can you afford another four years of Mr. Trudeau? I think the choice is between voting New Democrat or voting for Mr. Trudeau. You've seen that in the past six years on everything that matters, the things that really matter to you and your family鈥攖he cost of housing, the climate crisis, affordability鈥 on health care鈥攊n the past six years, what has Mr. Trudeau done? He鈥檚 chosen, by his actions, not to make those a priority,鈥 Singh said.

鈥淚 don鈥檛 want you to get caught up in all the despair and how bad things are. I want you to also believe and hope that we can make things better.鈥