Aboriginal groups in the Canadian Pacific province of British Columbia said on Thursday they had formed a united front to oppose all exports of crude oil from the Alberta tar sands through their territories.
The declaration is another political blow to the Canadian energy sector and Canada's right-of-center Conservative government after Washington decided last month to delay approving a pipeline carrying oil sands crude to the Gulf Coast.
It adds to the uncertainty over Enbridge Inc's planned C$5.5 billion Northern Gateway oil pipeline, which would move 525,000 barrels a day of tar sands-derived oil 1,177 km (731 miles) to the Pacific port of Kitimat, British Columbia.
Aboriginal groups, also known as First Nations, say they fear the consequences of a spill from the pipeline, which would pass through some of Canada's most spectacular mountain landscape. They also oppose the idea of shipping oil from British Columbia ports.
"First Nations, whose unceded territory encompasses the entire coastline of British Columbia, have formed a united front, banning all exports of tar sands crude oil through their territories," more than 60 aboriginal groups said in a statement.
Prime Minister Stephen Harper says the Northern Gateway - which would open up a new supply route to Asia - is important for Canada, especially after the United States delay to approval of TransCanada Corp's Keystone XL pipeline.
Washington announced the delay after a high-profile protest campaign against oil sands crude, which requires large amounts of energy to produce.
Aboriginal opposition is one of the biggest risks to Enbridge in its efforts to move Northern Gateway forward. The company has offered native groups equity stakes in the pipeline as well as large sums of money for community development.
Enbridge spokesman Paul Stanway said the affair had to be handled by government and regulators rather than by the company. "This is a ban that would have serious implications for the entire province of British Columbia," he said.
But groups such as the Yinka Dene Alliance and Coastal First Nations have said they will not support the project under any circumstances.
"We have banned oil pipelines and tankers using our laws, and we will defend our decision using all the means at our disposal," said Chief Jackie Thomas of Saik'uz First Nation, a member of the Yinka Dene Alliance.
Hearings into the Northern Gateway pipeline are due to start in January 2012 and could drag on for years. Even if Enbridge gets approval, native groups are likely to appeal the case through Canada's sluggish courts system.
Thursday's declaration could also affect a planned expansion of Kinder Morgan Energy Partners' Trans Mountain oil pipeline, which runs from Alberta to Vancouver. The company is seeking commitments from potential shippers for the project.
"We respect First Nations territories and we have always and will continue to extend an open invitation to First Nations along our pipeline and near our facilities to meet with us when and if our expansion plans move forward," said a company spokesman.
Federal Natural Resources Minister Joe Oliver, who strongly backs the Northern Gateway, said interested groups could make their views known to the review panel.
"It is a strategic objective of this government to diversify our energy exports. However, all regulatory processes will be followed before any final decision is made," he said in an e-mail.
(Editing by Janet Guttsman)