The demonstrators demanded an independent and public investigation of alleged overly aggressive police security during the international economic gathering in Toronto, Canwest News Service reported. More than 1,000 people were taken into custody at the G20 event, the largest mass arrest in Canadian history, Canwest said.
Protests also took place in Montreal and Halifax, with representatives from Greenpeace, Amnesty International, the Canadian Civil Liberties Association and the Ontario chapter of the Canadian Federation of Students in the crowds.
"Tens of thousands of people demonstrated peacefully to demand action be taken by the world's most powerful leaders on climate change, global poverty, maternal health, Indigenous peoples' rights and the privatization of education," Hamid Osman, Ontario representative of the Ontario student group, said in a news statement.
"Despite our rights to express ourselves and raise important concerns, many of us had our rights stripped away, and were subjected to police violence and arbitrary detention."