In the first major protest during the Group of 20 (G20) summit, at least 2,000 people marched on the downtown streets in the Canadian host city of Toronto on Friday afternoon.

A protestor calls attention to the loss of jobs in the US in downtown Toronto, June 25, 2010. [Chinadaily]

The protesters, mostly young people and many appearing to be college students, gathered in a local park around 2 p.m. Friday before starting to march toward the area where the main venue of the G20 summit lies.

Over 100 riot police holding shields blocked the way of the marchers at the intersection of Elms Street and University Avenue, forcing them to change direction at around 6 p.m..

Police patrols on cars, bicycles and horseback were also seen on the scene.

Some protesters, holding posters that read "Do You Want to Starve? We Need to Eat Too," told Xinhua that they were protesting against the high government spending on the hosting of the event.

The crowd remained largely calm and peaceful when they were halted, only chanting slogans and singing loudly.

According to an earlier report by local CBC News, the demonstrators claimed to represent more than two dozen causes, including environmental, economic and labor issues.

There were just a few minor confrontations and skirmishes with police, said CBC News, while CTV Toronto reported that police may have arrested a protester.

The Fourth G20 Summit is set to open in this largest city of Canada on Saturday afternoon, shortly after the closing of the annual Group of Eight (G8) summit in Huntsville, the Muskoka region -- about 2.5 hours of car ride from Toronto.

It is the first time for these two important international forums to be held back to back in one country.

The estimated cost of the summits reached some 2 billion Canadian dollars, far exceeding the original budget of over 100 million Canadian dollars. More than half of it was spent on security measures.