The chairman of a Native American tribe in South Dakota says members are “highly disappointed” Nebraska regulators approved the proposed Keystone XL oil pipeline after an oil spill near the tribe’s reservation.

Dave Flute is the tribal chairman of the Sisseton Wahpeton Oyate. Flute said Monday his tribe will stand with other tribal nations to oppose pipelines.

Nebraska regulators voted earlier Monday to approve a route for the pipeline through the state. The vote came just days after an estimated 210,000 gallons (794,913 liters) of oil spilled near the tribe’s land in South Dakota from TransCanada Corp.’s existing Keystone pipeline.

Nebraska officials have said state law didn’t allow regulators to consider pipeline safety as a factor in their decision.

TransCanada wants to build the nearly 1,200-mile Keystone XL pipeline from Canada through several states, including South Dakota. Opponents in South Dakota are also fighting the project in court.