First Nations leaders will not allow the proposed Enbridge and KinderMorgan pipelines to cross their unceded territory, saying they will stand in front of bulldozers if they have to.

'We'll do whatever it takes legally and otherwise'—Haisla elder, Gerald Amos

The pipelines would run from Alberta's oilsands to the B.C. coast, carrying oil to tankers for export to the US and Asia.

"Everyone involved — including myself — have made commitments that we'll do whatever it takes legally and otherwise," said Haisla elder Gerald Amos.

He said they will resort to civil disobedience to halt the pipelines.

"I am prepared to do as others have done before me in our communities and stand on the line to prevent any machinery moving onto the site."

Northern B.C. First Nations have long voiced their opposition to the pipeline, but on Thursday, 55 First Nations leaders from across B.C. signed a declaration promising to halt the proposed Enbridge and KinderMorgan pipelines.

Ta'kaiya Blaney, of the Sliammon First Nation, voices her concerns about a crude oil pipeline and tanker expansion during a gathering in Vancouver on Thursday. (Darryl Dyck/Canadian Press)

"These First Nations form an unbroken wall of opposition from the U.S. border to the Arctic Ocean," they said in a written statement.

Among the signatories is Chief Jackie Thomas, of Saik’uz First Nation, a member of the Yinka Dene Alliance.

"Harper wants to force pipelines through B.C., ignoring our rights and ignoring the majority of British Columbians. Well I have news for you Mr Harper: You are never going to achieve your dream of pushing pipelines through our rivers and lands and putting oil tankers on the coast."

The First Nations leaders say they are prepared to stand shoulder-to-shoulder in front of bulldozers to halt any pipeline construction.

Enbridge spokesman Paul Stanway says he hopes cooler heads prevail, and that environmental assessment hearings for the Enbridge pipeline don't focus on emotional pleas, but rather, stick to the facts.

"I don't believe that's how you make decisions that are in the public's interest."

The hearings begin in Kitimat in January 2012.

With files from the CBC's George Baker and Terry Donnelly