Prime Minister Stephen Harper says the world must act in the wake of an alleged chemical weapons attack in Syria that he blamed on the regime of Bashar al-Assad, or risk setting a precedent "very dangerous for humanity."

He also spoke passionately against the notion that the United Nations Security Council must be unanimous in its call for force in Syria and took aim at Russia in particular for using its Security Council veto to water down any attempt to deal with the crisis.

Harper blamed last month's attack against civilians on the regime of Syrian President Assad, as he spoke at the close of the G20 Summit in St. Petersburg, Russia.

Harper said he suspects Assad has gradually been increasing his use of chemical weapons as the bloody conflict in Syria hits a stalemate, pointing out there is much that is troubling aside from a single suspected attack.

"I think what we have been seeing over the past several months is the Syrian government, which finds itself in a stalemate, believes that it can win... the civil war in Syria through the use of chemical weapons. And they have been step-by-step ratcheting up that usage to see if anyone is going to challenge it," Harper said.

John Baird speaks to The House Tune in to CBC Radio One's The House with Evan Solomon at 9 a.m. Saturday (9:30 in Newfoundland) to hear an exclusive interview with Foreign Affairs Minister John Baird.

"And I fear that if no one does challenge it, they will use chemical weapons on a scale way beyond anything we have seen to date to win that war. And if that ever happens, I believe, as I told the leaders that last night, that is a precedent that humanity will regret for generations to come."

Harper and Foreign Affairs Minister John Baird have said Assad will pay for his actions, but they've also said Canada will not take on its own mission in Syria. Asked what Canada is doing aside from urging others to take action, Harper said the government is arguing "vigorously" on the matter with countries that aren't allies.

"All we're doing, we're not just supporting our allies, but trying to argue vigorously with those on the other side," Harper said.

The U.S and other allies have identified a course of action, he said, that isn't without risk, but has a limited scope and duration of action.

"It's also the kind of action that, given the nature of the assets that would be deployed, that Canada could not contribute and is not being asked to contribute to," Harper said.

Baird has said any mission is likely to involve armed drones and missiles, neither of which Canada has.

Putin's chance to make change

Meanwhile, the Canadian general who led the NATO mission against Libya warned that countries looking at a military strike have to consider unintended consequences.

Retired Lt. Gen. Charles Bouchard suggested Friday on CBC News Network's Power & Politics that military action in Syria may lead to consequences from Lebanese-based Hezbollah or the regime in Iran.

Syria, he said, has a much better-equipped military than the former regime in Libya. And Assad knows a strike may come, so has likely taken measures to protect military equipment.

"I think from a strategic perspective, there's certainly no element of surprise. In fact, I would think that by now they've already taken all the measures, dispersals, camouflage.... It's already taken place. One can only assume that because they've seen this one coming. Now the next question is what will come next," Bouchard said.

This is Russian President Vladimir Putin's chance to make a global change, he added.

"The key to the solution in this part of the world really lies with President Putin and Russia. Here is a chance for him to make a change on a global level, in fact to the point of possibly a Nobel Peace Prize.... He could bring peace up there or at least bring the government to the table to negotiate and find a peaceful solution, because the military will not bring a solution in and of itself."

An individual country could take action on its own, he said, but it's best to have a consensus — something the world hasn't seen among NATO or UN Security Council countries.

Different countries could provide political or military support, he added.

"All of this group will work together, because it's not just about the strike itself, but also what will come thereafter in terms of negotiations and discussions that must take place to follow on," Bouchard said.

'Not prepared' to accept Russian veto

Harper has chided countries that have blocked the UN Security Council from authorizing force against Syria throughout a brutal crackdown by Assad's regime. Those countries include Russia and China, though in his remarks on Friday, Harper didn't immediately name them.

"Their view is that the absolute authority of the [UN] Security Council is necessary for any action — even if that means no action at all will be taken.

"We are simply not prepared to accept the idea that there is a Russian veto over all of our actions. And so that's the fundamental difference of opinion here," he said.

Prime Minister Harper, right, at the G20 summit with Foreign Affairs Minister John Baird, who has said Canada doesn't have the weapons to partake in any of the likely missions against Syria. (Adrian Wyld/Canadian Press)

"There are times in politics — it's true in domestic politics, but I think it's true in international politics — there are times in politics where process answers are not good enough. And to simply say, 'Well, there's a UN process and even if it fails, and fails on the most extreme and dangerous level, we still must follow the process,' that's not acceptable. That is not acceptable in our judgment in this circumstance."

In an interview to air Saturday on CBC Radio One's The House, Baird sounded pessimistic about whether Russia will change course on Syria.

"The UN Security Council will seek to grapple with this issue. I'll be frank, I'm not optimistic that we can break the Russian veto," Baird said to Evan Solomon, host of The House.

Describing the discussion among leaders at the summit, Harper called the talk about Syria "extremely frank, but I think also respectful... of what are very large divergences of opinion around the table."

"We share the view of our allies that the use of chemical weapons on an unprecedented scale by the Syrian regime constitutes a very troubling development," Harper said Friday.

"And if it is not countered, it will constitute a precedent that we think is very dangerous for humanity in the long term. And so, obviously, we are very supportive of those of our allies who want to take action to try and prevent this development from going further, trying to dissuade the Syrian regime from this course of action."

$45M for refugees

Harper also announced an additional $45 million in funding for humanitarian organizations to provide food, water, shelter and other help to refugees from the region.

The civil war Syria has driven an estimated two million people into neighbouring Lebanon, Jordan and Turkey. The extra $45 million brings the total committed by Canada since January 2012 to $203.5 million.

The G20 Summit, which wrapped up Friday, provides a regular opportunity for the leaders of the 20 biggest economies in the world to discuss economics, but the Syrian crisis drove many governments to send their foreign affairs ministers along to discuss possible solutions.

Canada is one of the signatories of a joint statement on Syria issued by the White House on Friday that condemns the alleged attack that "that claimed the lives of so many men, women, and children" and places the blame squarely on the Assad regime.

"The evidence clearly points to the Syrian government being responsible for the attack, which is part of a pattern of chemical weapons use by the regime," the statement said.

"We call for a strong international response to this grave violation of the world’s rules and conscience that will send a clear message that this kind of atrocity can never be repeated. Those who perpetrated these crimes must be held accountable," said the statement, which also expressed support for the United States' recent efforts to "reinforce the prohibition on the use of chemical weapons."

Other signatories include Australia, France, Italy, Japan, Republic of Korea, Saudi Arabia, Spain, Turkey and the United Kingdom.