OTTAWA/TORONTO (Reuters) - An indigenous community opposing construction of a gas pipeline in Canada launched a legal challenge on Wednesday over the climate impact of fossil fuel projects on indigenous territories while Prime Minister Justin Trudeau urged pipeline protesters blocking rail lines to find a quick solution.

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Hereditary chiefs of Wet’suwet’en Nation asked the federal court to declare that “Canada has a constitutional duty to keep the country’s greenhouse gas emissions within the Paris Agreement limit.”

The hereditary chiefs are at odds with the indigenous community’s elected officials, who have supported the Coastal Gaslink route of the pipeline project in British Columbia. The hereditary chiefs say that they, and not the elected officials, hold authority over traditional lands.

All of the elected indigenous band councils along Coastal GasLink’s route support the project.

Anti-pipeline protests have spread across Canada in support of Wet’suwet’en Nation’s opposition to the proposed pipeline.

Demonstrators near Canadian National Railway (CN) tracks in Ontario, Canada’s most populated province, disrupted passenger trains and goods transportation for a sixth straight day on Wednesday. Ontario police on Tuesday warned they had a court injunction ordering that the area be cleared.

About a hundred supporters protested outside the Supreme Court in British Columbia Wednesday shortly after the legal challenge was launched.

Trudeau, during an official visit to Senegal, said that while peaceful protest is a fundamental part of Canada’s democracy, the rule of law must be respected.

“That’s why I am encouraging all parties to dialogue to resolve this as quickly as possible,” he said in Dakar at a news briefing televised by the Canadian Broadcasting Corp.

The protests against the pipeline have turned into a flashpoint for indigenous rights demonstrators. Trudeau has said it is a priority for his government to repair relations with First Nations and to champion indigenous rights.

The C$6.6 billion ($4.97 billion) pipeline at the heart of the dispute would move natural gas from northeastern British Columbia to the Pacific Coast, where the liquified natural gas Canada export facility led by Royal Dutch Shell is under construction. The pipeline will be operated by TC Energy Corp.

Canada’s transport minister, Marc Garneau, said in a statement on Wednesday the court injunctions secured by CN to resume services must be respected.

CN, the country’s biggest railroad, said on Tuesday it may be forced to shut down parts of its network unless the blockades end.

The Canadian Chamber of Commerce called for an “immediate end” to the blockades. “Canada’s supply chains are being severely damaged by the continuing interruptions,” the chamber said. Coastal GasLink said on Tuesday that construction of the pipeline is expected to resume this week.