Two Ojibwe bands have petitioned the Minnesota Court of Appeals to suspend state regulators' approval of Enbridge's new Line 3 and stop construction of the controversial pipeline across northern Minnesota.

The petition filed late Tuesday by the Red Lake Band of Chippewa and the White Earth Band of Ojibwe is the second such filing in the past week by pipeline opponents to shut down construction on the $2.6 billion pipeline. Enbridge earlier this month started work on the replacement for the aging and corroding current Line 3 earlier this month.

In a separate filing Wednesday, Friends of the Headwaters also asked the state appellate court to halt the pipeline, citing "irreparable" environmental harm.

The two bands — plus the Sierra Club and the Indigenous environmental group Honor the Earth — last week sued the U.S. Army Corps of Engineers in U.S. District Court in Washington, D.C., asking for a preliminary injunction to stop construction of Line 3.

The Minnesota Public Utilities Commission (PUC), the state's primary pipeline regulator, approved Line 3 in February after nearly six years of review.

Several groups, including the Minnesota Department of Commerce, challenged that decision before the Minnesota Court of Appeals, arguing among other things that the PUC didn't properly

evaluate Enbridge's long-term oil demand forecast.

Red Lake and White Earth have now asked the appellate court to stay the PUC's order, saying they will be "irreparably harmed" if construction is allowed to continue. The appellate court won't hear the appeal until sometime this winter at the earliest.

"The tribes anticipate that this court would issue a final order in approximately July 2021, at which time construction will likely be complete or nearly complete, such that in the event of reversal tribes would not obtain the relief they seek," Red Lake and White Earth said in legal filing.

Calgary, Alberta-based Enbridge expects to complete construction by the end of September. More than 3,000 workers already are building the 340-mile pipeline.

In a statement, Enbridge strongly objected to efforts to stop construction. "There is no legitimate basis for this filing, which fails to recognize the exhaustive and meticulous review of the Line 3 Replacement Project by the Minnesota Public Utilities Commission, and only seeks to delay an essential maintenance and safety replacement project."

In a court filing, the tribes said that without a stay, "their treaty-protected interests in the land, waters, plants, animals and environment" would be destroyed or damaged by construction — as would their cultural and religious rights.

The pipeline's potential to degrade lakes, rivers and streams would harm "Native Americans' spiritual connectedness to water, a sacred element to native culture," the filing said.

The Corps on Nov. 23 issued its permit for the discharge of dredged and filled material into U.S. waters during Line 3's construction. It was the last major approval that Enbridge needed to start building the pipeline, which will transport Canadian oil to the company's terminal in Superior, Wis.

Environmental groups and some Indian bands have said the pipeline — which follows a new route — will open a new region of pristine waters to the prospect of oil spills, as well as exacerbate climate change by allowing for more oil production.

Enbridge has said the new pipeline is a critical safety enhancement. The current Line 3 is so corroded it is running at only half of capacity. The new pipeline would restore full oil flow.