A federal judge last week ordered Ruby Montoya, a 32-year-old climate activist, to serve six years in prison for her role in damaging the Dakota Access Pipeline

More than 380,000 gallons of oil have spilled from a leak in the Keystone pipeline in North Dakota this week, officials said.

For months, the International Indigenous Youth Council, known for its commitment to peaceful action, has helped steer the Standing Rock Sioux Tribe's efforts to halt the Dakota Access pipeline.

Oil could flow through the pipeline as soon as next week.

Indigenous activists erected a tipi camp beside the Washington Monument today.

Trump has said Keystone steel "comes from the U.S., or we're not building it."

The legal opinion was withdrawn two days before an easement was approved.

Forty-six people were arrested today, authorities said.

The deadline to evacuate the Oceti Sakowin camp was Wednesday at 2 p.m.

Announcement comes amid legal battle between company and Indian tribes.

Dakota Access pipeline protesters at the Standing Rock Sioux Tribe reservation in North Dakota met with state representatives Thursday.

The camp needs to be evacuated by February 22.

Tribe joins a motion filed Thursday by Cheyenne River Sioux Tribe.

A judge found no irreparable harm to the tribes if construction goes on.

A Native American tribe has filed the first legal challenge to block the nearly finished Dakota Access Pipeline from moving forward.

Opponents of the Dakota Access Pipeline believe the easement cannot be granted legally at this time.

The controversial final phase of the pipeline has been on hold.

The Army said it has not yet granted the easement needed to finish the pipeline.

A court hearing is scheduled for early next week.

Record levels of snow are expected in the area, which could compromise safety.

The company seeks to protect the pipeline from potential terrorists.

About 76 "rogue" protesters were arrested Wednesday near the Dakota Access Pipeline in North Dakota, authorities said.

About 20 protesters were arrested after refusing to disperse from the property.

The actions drew applause from pipeline supporters, condemnation from opponents.

ABC News photographed Red Cloud’s visit in December to the Standing Rock Reservation where he installed solar air furnaces to help keep protesters warm.

Army Corps has denied the easement needed to finish the controversial pipeline.

Protesters have been ordered to leave the area by today.

Stars cheer decision by Army to deny approval for Dakota Access Pipeline.

At least 2,000 veterans arrived at the protests this afternoon.

Authorities have warned that protesters would be arrested starting Monday.

As evacuation deadline looms, veterans and civil rights observers converge.

Actress criticized the holiday and treatment of Native Americans over centuries.

For Native American activists, Thanksgiving brings back difficult memories.

Broken treaties are at the heart of the protests at Standing Rock.