More than 100 protesters were arrested Monday after trying to enter the House of Commons during a demonstration on Parliament Hill against a proposed oilsands pipeline project.

Hundreds of people flocked to the Hill to voice their displeasure with TransCanada's Keystone XL pipeline project, a $7-billion plan to ship crude oil from Alberta to Texas.

Greenpeace Canada spokesman Peter McHugh promoted the event as "a historic mass act of civil disobedience over the tarsands," which also included members from the Council of Canadians.

But the attempt by protesters to jump a fence and enter the Centre Block was orderly. The CBC's Karina Roman said there was even laughing and joking between police officers and those taken into custody.

RCMP officials said more than 400 people attended the protest, and 117 people were arrested, charged with trespassing and released.

Rochelle Sauvé said she and a busload of her friends from Peterborough, Ont., climbed the fence and were arrested, ticketed $65 and banned from Parliament Hill for a year. She said it was worth it.

"I hope the actions of those who choose to sit-in today can act as an inspiration to people across Canada," said Sauvé.

Gitz Deranger was one of many First Nations protesters also in attendance. He said his community near Fort Chippewayan is plagued by health problems as a result of its proximity to the oilsands.

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Dozens of RCMP police officers and security guards have gathered on Parliament Hill to deal with hundreds of oilsands protesters. (CBC)

"Our indigenous way of life is being threatened by the tarsands. You destroy our land, you destroy us," said Deranger.

Large police presence greets protesters

The civil disobedience was inspired by action in Washington, D.C., in late August where Canadian actress Margot Kidder and dozens of others were arrested.

Conservatives call protesters 'extremists'

Conservative MP Jason Kenney described the protesters as "extremists" in a post on his Twitter account Monday.

"Sad to see about 200 extremists on the Hill today who want to kill livelihood of hundreds of thousands of Cdns [sic] working in the energy sector," he wrote.

Conservative MP David Anderson, the parliamentary secretary to Natural Resources Minister Joe Oliver, also called the protesters extremists in response to a question from NDP environment critic Megan Leslie.

Outside question period Leslie said she believed the protesters we're simply expressing their beliefs.

"They are trying to say something," said Leslie. "We are trying to say something in the House as well. This pipeline expansion will result in uncontrolled expansion of the oilsands and that's something that we question. There are serious problems with this pipeline, both environmentally and when it comes to jobs for Canadians."

Protesters, who signed up at a website called Ottawa Action, arrived around 10 a.m. for a sit-in around the Centennial Flame.

Dozens of RCMP officers and security guards were also patrolling Parliament Hill.

Organizers hosted a seven-hour training session for protesters Sunday that was closed to the media.

"Participants are responding to a call to action for a large peaceful protest where many will risk arrest to tell the Harper government they don’t support his reckless agenda," said McHugh in a news release.

"Participants will also use this action to tell Harper we need to turn away from the tarsands and start building a green-energy economy that respects indigenous rights and prioritizes the health of the environment and communities."

The event featured more than 20 environmental and indigenous organizations and boasts the support of a dozen Canadian celebrities.

Maude Barlow, chair of the Council of Canadians, has said the government needs a conversion plan to move to alternate energy sources.

"Tarsands mining has destroyed much of Alberta's water table and will put the fragile Ogallala Aquifer [the world's largest known aquifer] in peril. We join with the millions of Americans who oppose the expansion of this deadly industry," she said in a statement.

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Police arrested dozens of protesters who tried to climb over a barricade and enter the House of Commons, but there was no violence. (Ashley Burke/CBC)

Greenpeace co-founder supports oilsands in statement

But in a statement released by the Canadian Association of Petroleum Producers Monday, the co-founder of Greenpeace supported the oilsands.

Former leader Patrick Moore, who has written a book on why he left Greenpeace after 15 years, has publicly denounced Greenpeace in the past calling them anti-human and "anti-science."

"I've seen the land reclamation progress at oilsands sites," said Moore in the statement, "It's a necessary, staggeringly complex process and evidence shows the land will be reclaimed as thriving ecosystems after oil sands are developed to help meet the world's growing energy needs."

Ottawa police warned motorists to avoid the area near Parliament Hill during the mass protest.

The last large Greenpeace event on Parliament Hill led to 20 arrests after protesters climbed the West Block and unveiled large banners advocating government action to combat climate change.