ST. PAUL, Minn. (AP) _ An environmental group is asking Minnesota utility regulators to investigate Enbridge's additions to its existing oil pipeline capacity which could make the company's controversial new $2.6 billion pipeline unnecessary.

A filing by the Indigenous organization Honor the Earth with the Minnesota Public Utilities Commission says Enbridge made no mention of its capacity additions during hearings for the pipeline, a replacement for the aging Line 3, which runs from Alberta, Canada, to Enbridge's terminal in Superior, Wisconsin.

Tuesday's PUC filing is the latest salvo in a six-year battle over the new pipeline.