U.S. and Canadian tribes on Wednesday will sign an international declaration of opposition against the Keystone XL oil pipeline.

Indigenous tribal leaders will assemble in Calgary, Alberta, home of pipeline builder TransCanada, to sign the 16-page declaration.

The tribes signing the declaration will include Canada's Blackfoot Confederacy and the Great Sioux Nation and Ponca tribes from the United States, calling the joint declaration a historic undertaking.

President Trump, as one of his first actions as president, signed orders directing the State Department to approve a permit to construct the segment of the Keystone XL oil pipeline that extend from Canada into the United States. The pipeline had been delayed more than seven years under former President Barack Obama, before he finally rejected the permit ahead of the 2015 Paris climate change agreement.