TORONTO - Several hundred First Nations protesters waved flags, including upside-down Canadian flags, and pounded on drums Thursday as they marched through downtown Toronto.

Shouting, "No G20 on stolen native land!" the marchers headed along Bay Street carrying placards, banners and Mohawk Nation flags as well as the upside-down Maple Leaf.

Police with bicycles walked along the route beside the marchers, using their bikes to keep people on the street.

The protesters, whose ranks grew by the hundreds as the day wore on, are hoping to draw attention to aboriginal issues from international media covering the G8 and G20 summits.

They are calling for control of land they claim as their own, and urging the government to investigate the disappearance of some 500 aboriginal women.

"We're here basically to bring attention to the impact that G8 and G20 meetings have, and the effect their social and economic policies are going to have on indigenous people, lands and resources," said Russell Diabo, a Quebec Mohawk who is spokesman for Defenders of the Land.

"We have a lot of unresolved issues we need to see addressed domestically, without Stephen Harper talking about going overseas and dealing with development there," added Diabo.

Also in the large crowd were environmental protesters, including Alaynah Smith of Midland, Mich., who carried a sign that read: "Stop the Alberta tarsands."

"They should stop the tarsands because it's wiping away (aboriginal) resources," she said, referring to the oil-extraction project.

"It's making it so they can't drink their water and they can't live and conduct life as they used to."

Michael, a tourist from Israel, stumbled onto the march as he was walking downtown.

"I didn't know that aboriginals had complaints," he explained as he snapped some pictures. "I guess I should read a bit to build my own opinion."

Protesters said a blockade of Highway 403 between Toronto and Hamilton planned for Thursday has been cancelled until further notice.

Provincial police said a planned blockade of the Trans-Canada Highway near Thunder Bay, Ont., has also been cancelled.

Editor's note: Many of the comments below, calling for "arrests," were published in an early version of this story which said  highway blockades were planned for later in the day.

Those blockades were later cancelled; and the story was updated with news of a peaceful march in downtown Toronto.