CHICAGO (AP) — Protesters opposed to the four-state Dakota Access pipeline are demonstrating in downtown Chicago.

The crowds gathered Friday in a plaza and then marched through downtown streets. Demonstrators say they’re rallying in solidarity with Native Americans fighting to stop the pipeline that would run from North Dakota to Illinois.

A federal judge on Friday rejected a request by the Standing Rock Sioux tribe to halt construction of the $3.8 billion pipeline. But soon after, the federal government stepped in. Federal officials have ordered work to stop on one segment and asked the Texas-based company building the pipeline to pause action on a wider span that an American Indian tribe says holds sacred artifacts.

The Standing Rock Sioux tribe says the pipeline threatens their drinking water and has disturbed sacred sites.