Leaders of the Blackfoot Confederacy and Great Sioux Nation signed a declaration against the Keystone XL pipeline on May 17 in Calgary.
The 16-page declaration highlights their treaty rights and their opposition to the proposed $8-billion pipeline, which would move Canadian crude south to Nebraska, where the pipeline would connect with an existing Keystone pipeline network that would take the oil to Texas Gulf Coast refineries.
The document also includes opposition to the expansion of the Alberta oilsands.
First Nations leaders from both sides of the border are calling for more dialogue and consultations on the project, which runs through their traditional lands.
The leaders say their coalition represents thousands of First Nations people in opposition to the TransCanada project and wanted to be in the company's hometown of Calgary to express their concern.
"We don't oppose development and we don't oppose other exploration opportunities for various tribes at their discretion," said Piikani Nation Chief Stanley Grier, of the Blackfoot Confederacy.
"But rather what we are saying here, with this declaration… is there needs to be free, prior and informed consent when it relates to Indian country."