As focus shifts to the G20 summit -- with its priority of stabilizing the world economy -- leaders were downplaying reports of disagreements in their ranks.

Talking to reporters at the conclusion of the first of this weekend's major summits, host Prime Minister Stephen Harper struck an optimistic note.

"Given the nature of the events and the challenges that confront us, I have never seen a G8 more fundamentally united in purpose, more frank in its discussions," Harper told reporters at the end of the G8 summit in Huntsville Saturday afternoon.

"And I think that will carry forward into the G20."

The prime minister's comments came as leaders from the G8 nations -- Britain, Canada, France, Germany, Italy, Japan, Russia, United States -- prepared to leave Muskoka for the larger Group of 20 nations summit in Toronto.

Harper was buoyed by the consensus he achieved on several of his priority summit issues, including stern words for Iran and North Korea. But considering the state of negotiations leading up to the larger summit, the prime minister's chances of achieving a similar result among the more fractious membership of the G20 appear slim.

Considering the group's top priority is restoring global finances to long-term health, there's little disagreement that something must be done to stabilize the world economy, but that's where the agreement ends.

Harper is hoping leaders of the G20 -- including China, India and Brazil -- will agree to halve deficits by 2013 and bring debt-to-GDP ratios to sustainable levels by 2016.

"What we must avoid at just about all cost is some kind of cataclysmic event along the lines of Lehman Brothers," Harper told reporters at the Deerhurst Resort in Muskoka.

"We can't afford some particular event, that would cause a series of cascading events and a downward spiral of confidence in markets."

After weeks of pre-summit meetings, G20 nations remain divided among those who would continue spending, led by the U.S. and those who have already begun slashing deficits, including Japan, Germany and Britain.

Talking to reporters at a press conference in Toronto Saturday, U.S. Treasury Secretary Timothy Geithner downplayed reports of any fundamental disagreements. Nations gathered for discussions in Toronto have "more in common than in difference," Geithner said.

"Everybody is still working to ensure they are repairing the damage of this crisis."

French President Nicholas Sarkozy echoed the sentiment, insisting there is no difference in opinion between Europe and the U.S.

"The question today is on the reduction of debt and deficits. No one disputes the necessity. The question is what way and how deep," he said.

Other potentially divisive issues on the G20 table include:

• pressure on China to relax control over its currency exchange rates
• a push for banks to increase their capital holdings
• calls for a levy on banks geared toward avoiding future taxpayer-funded bailouts
• moves for structural reforms, including increased financial regulation and oversight

In the hours between summits, Harper met with the so-called B20 Summit -- a parallel meeting of global business executives.

Following an official reception, G20 leaders, business executives, finance ministers, top negotiators and leaders' spouses are all holding separate dinners at the historic Royal York Hotel.

Official meetings are being held behind a security cordon that virtually guarantees leaders will be spared the effects of protests that raged in the city's downtown core Saturday afternoon.

Thousands of anti-G20 demonstrators staged a loud, peaceful march that ultimately turned violent when a splinter group of black-clad masked demonstrators, broke off from the main group. The group vandalized storefronts and clashed with police at the edges of the security zone established around the convention centre where the G20 summit is being held.

With files from The Canadian Press