U.S. military veterans have thrown down the gauntlet to the Trump administration, vowing that the Dakota Access Pipeline will “not be completed— not on our watch.”

Veterans Stand, a group of vets who have vowed to protect the pipeline protesters of the Standing Rock Sioux Nation and supporters, ominously threatened the possibility of more “boots on the ground” at the site — but also repeated their commitment to nonviolent action. The group is capable of calling up several thousand veterans to the protest site.

“We are committed to the people of Standing Rock, we are committed to nonviolence, and we will do everything within our power to ensure that the environment and human life are respected,” spokesman Anthony Diggs told CNBC. “That pipeline will not get completed. Not on our watch.”

The latest defiant declaration follows the arrest Wednesday of nearly 80 protesters camped out at the demonstration site near the town of Cannon Ball, North Dakota, amid the Trump administration’s determined press to push through the controversial pipeline. Local law enforcement said the protesters were arrested when they moved from one of their camps onto land owned by pipeline operator Energy Transfer Partners.

The renewed pressure on the protesters drove donations to a GoFundMe site established last week by Veterans Stand to $105,000 in six days.

Trump late last month signed an executive order to advance construction of the pipeline just weeks after the Army Corps of Engineers had held up the pipeline by calling for a new environmental review that could taken up to two years. Financial disclosure filings by the president have revealed that as recently as last summer he owned shares in Energy Transfer Partners, and company CEO Kelcy Warren contributed $100,000 to elect Trump, Mother Jones reported.

The arrests at the protest site occurred the day after Acting Secretary of the Army Robert Speer ordered the U.S. Army Corps of Engineers to abandon the environmental review and grant Energy Transfer Partners the final easement it needs to complete the last stretch of the $3.7 billion, 1,172-mille-long pipeline.

Protesters have vowed to stand their ground. The Standing Rock tribe says the planned section of the pipeline where they’re encamped would travel through sacred burial grounds, would violate an 1857 treaty and would threaten precious water resources. They have vowed to launch a new legal challenge to the pipeline, arguing that the Army Corps of Engineers lacks the authority to halt the environment review that it had just launched weeks ago.

Before Trump moved into the White House, the Corps denied the easement to the pipeline company in early December, declaring that the best option would be to consider other routes by conducting a thorough environmental review.