With his order to revive the Keystone XL (KXL) pipeline, President Donald Trump "has declared war on Indigenous nations across the country," one Cheyenne River Sioux organizer said Monday.

But he'll be met by a fierce native resistance movement that "will not back down," said the organizer, Joye Braun, on a press call organized by the Indigenous Environmental Movement (IEN).

Trump signed executive orders last week advancing the controversial KXL and Dakota Access (DAPL) pipelines, prompting widespread outrage and vows of bold resistance from the Indigenous activists, climate campaigners, and countless others who have fought against both projects. What that opposition will look like came into sharper focus on Monday.

"Make no mistake: resistance to the toxic Keystone XL pipeline will only grow stronger," declared Dallas Goldtooth, IEN's Keep it in the Ground organizer. "We will mobilize, fight back, we will resist the Keystone XL pipeline. We plan to create camps along the Keystone XL pipeline route to fight this pipeline every step of the way."

A press release from his organization confirmed that Indigenous groups are "organizing spiritual camps to resist the Keystone XL pipeline up and down the pipeline route, in addition to reviving the Standing Rock camp" which sprang out of resistance to DAPL and at its height housed thousands of protesters.

Eriel Deranger of the Athabasca Chippewayan First Nation added: "My nation is not taking Donald Trump's new memorandum on Keystone XL lightly—we will fight back through through the courts, protests, and any means available and necessary."

Following Trump's orders last week, IEN vowed to launch a "massive mobilization and civil disobedience on a scale never seen of a newly seated president of the United States." Or perhaps of any president who's ever faced an anti-pipeline protest.

Indeed, with more than 1,073 water crossings, "any controversy over the proposed $8 billion Keystone XL pipeline holds the potential to make the Dakota Access fight seem like a warm-up exercise," South Dakota's Rapid City Journal reported on Sunday.

The paper continued: