Facebook is seeing a spike in check-ins from the Standing Rock Sioux reservation in Cannon Ball, North Dakota where demonstrators are attempting to block the construction of a pipeline on the land, which is disputed between the Army Corps of Engineers and the tribe.

The check-ins are being used as a new tactic in the protests against the $3.8 billion Dakota Access Pipeline that some believe will confuse law enforcement and hinder them from tracking protestors on social media.  The Morton County, N.D., sheriff’s department denies that it follows the movements of protestors.

By Monday afternoon, 600,000 people checked in on Facebook at Standing Rock, according to CNN.

For months now, opponents of the four-state pipeline have been camping in this area about 50 miles south of Bismarck. They worry the pipeline will disturb cultural artifacts and threaten drinking water sources on the Standing Rock Sioux’s nearby reservation and downstream.

The pipeline’s operator, Texas-based Energy Transfer Partners, insists the project is safe. The tribe is fighting the pipeline’s permitting process in federal court.

Protests erupted into a clash last week that resulted in 140 arrests, authorities said. Some demonstrators torched three vehicles on a bridge, creating a blockade that effectively cut off easy access to the pipeline construction zone and made it far harder for the tribe and nearby residents to get to Bismarck for errands and medical appointments.

Tribal elders condemned the destruction of the vehicles, said Emmett White Temple, a 55-year-old member of the Standing Rock Sioux.

“People were getting chewed out for the aggression,” he said of a meeting Sunday at the main protest camp. “We have to keep on with prayer, but those people are still digging that pipeline,” he said. Others believe “violence gets action.”

Cody Hall, a former spokesman for one of the encampment’s factions, said the entire camp must remain united to successfully fight the pipeline. He said the violence seen Thursday was “expected.”

“I’m not going to say anything bad about the fire being put up,” Hall said. “It happens and we are dealing with it.”

This story appeared earlier on JETMag.com.