SIOUX FALLS, S.D. -- Foes of the Keystone XL oil pipeline may appeal a South Dakota judge's decision upholding state regulators' authorization of the project where it crosses the state.

Two groups said Friday they are weighing whether to raise the issue to the state Supreme Court. A judge last month affirmed a Public Utilities Commission decision that was challenged by Native Americans, landowners and others.

Robin Martinez, an attorney for conservation and family agriculture group Dakota Rural Action, called the judge's decision a "disappointment."

Terry Cunha, a spokesman for pipeline developer TransCanada Corp., praised the decision, saying the project offers substantial economic benefits.

Judge John Brown wrote that the issues opponents raised have been adequately addressed by the commission or aren't appropriate to be addressed in the case.