Hundreds gathered at the State Capitol in Denver on Thursday night to protest the Dakota Access oil pipeline, calling for construction of the controversial project to come to a halt.

Protesters in Denver, a great many of them Native Americans, stand in solidarity with members of the Standing Rock Sioux tribe which is trying to stop the pipeline in North Dakota. Native Americans from across the United States have gathered at the confluence of the Cannonball and Missouri rivers, in the Standing Rock Sioux Reservation, to make a stand against the $3.8 billion pipeline.

State Rep. Joe Salazar, D-Thornton, was among the speakers who addressed the crowd on the west steps of the State Capitol.

Salazar rallied the crowd, questioning the safety of oil pipelines and fracking among other means of extracting and transporting fossil fuels. Touching on a recent Colorado Oil and Gas Association statement on oil pipeline safety, Salazar described it as “being full of lies.”

Citing an oil spill in the Yellowstone River, a pipeline explosion in New Mexico and recent earthquakes in Oklahoma, which some say are caused by fracking, Salazar asked: “What is the definition of safe?”

The crowd roared in support and approval of the question.

Native Americans in ceremonial dress danced to drums leading protesters from the Denver City and County Building along Colfax Avenue across Civic Center to the Capitol.

Some protesters carried signs, “Save our Water” and many chanted, “you can’t drink oil, water is life,” as they marched.

The marchers descended on the Capitol from all four directions and on the west steps they numbered about 500. Marchers from the west wore black; from the north, red; the east, yellow; and the south, white. Sage was burned, a song and speech was given in Native American tongue.

At one point some in the crowd chanted: “We stand with Standing Rock.”

“Look at you, every face of our nation is represented here,” Salazar told the crowd, which included families and children.

Salazar told the crowd that he works in the Capitol, in the “halls of power.” But it’s “nothing quite as powerful as what we see here.”