Opponents of the Keystone XL pipeline vowed on Thursday to block construction of the controversial project if Nebraska regulators approve the proposed route later this year.

Nebraska regulators wrapped up a final public hearing a day early on Thursday on TransCanada Corp's (TRP.TO) proposed Keystone XL pipeline after four days of contentious exchanges between lawyers. They will make their final decision by Nov. 23.

After the hearing, two dozen landowners and other pipeline opponents vowed non-violent civil disobedience if the commission rules in favor of TransCanada. The action, they said, would be similar to months-long protests in North Dakota led by the Standing Rock Sioux tribe against the Dakota Access pipeline.

"Standing Rock was a dress rehearsal compared to what this will be," said Jane Kleeb, chair of Nebraska's Democratic party and founder of anti-pipeline group the Bold Alliance, her voice cracking. "We are not going to let an inch of foreign steel touch Nebraska soil."

The proposed 1,179-mile (1,897-km) pipeline, linking Canada’s Alberta oil sands to U.S. refineries, has been a lightning rod of controversy for nearly a decade.

The project has pit landowners and environmentalists worried about greenhouse gas emissions, oil spills and environmental contamination, against business advocates who say it will lower fuel prices, shore up national security and bring jobs.

Lawyers representing about 90 landowners opposed to the pipeline that would traverse their farms as well as those for TransCanada sparred for four days in a court-like hearing, presided over by a retired judge.

Intervenors in the hearing ranged from the landowners - mainly ranchers and farmers - to native American tribes and TransCanada representatives. Each group made their case to the five elected members of the Public Service Commission about whether or not the proposed pipeline was in the "public interest."

Just recently, TransCanada officials said they would only decide in December whether to proceed with the project after gauging demand from oil shippers and awaiting a decision from Nebraska's Public Service Commission.

Nebraska Governor Pete Ricketts, who was on a five-day mission to Canada this week, said he was optimistic the commission will give the green light to Keystone XL, calling it "the safest pipeline ever built."Canadian pipeline export capacity is currently about 4 million bpd, and producers are matching that with 4 million bpd of export-ready output, according to the Canadian Association of Petroleum Producers industry lobby group.

The group said oil supply available for export is expected to grow to 5.5 million bpd by 2030, and the industry wants more pipeline to accommodate it.

But since Keystone XL's rejection by the previous U.S. administration, alternatives have come into play, such as Kinder Morgan's (KML.TO) Trans Mountain pipeline and Enbridge's (ENB.TO) Line 3.