B.C. politicians, Indigenous leaders and environmentalists say the future of Kinder Morgan's Trans Mountain pipeline is in doubt.

On Sunday the company announced it would suspend all "non-essential activities" and related spending for the Trans Mountain pipeline project, citing ongoing opposition from the British Columbia government.

"I'm greatly encouraged by this news," said Grand Chief Stewart Phillip with the Union of B.C. Indian Chiefs.

"In many ways I think this is the first time Kinder Morgan has appreciated the intensity and the reality of the broad-based and deeply entrenched opposition to the Kinder Morgan Trans Mountain pipeline project here in British Columbia."

On Saturday, Stewart joined protesters at a Kinder Morgan work site in Burnaby. RCMP say about 200 people have been arrested around Trans Mountain facilities in Burnaby since mid-March.

On Sunday though, Kinder Morgan said its decision was largely based on the B.C. government's legal challenges to the pipeline and the need to protect its shareholders.

B.C. Premier John Horgan told a news conference in Victoria the ongoing protests, demonstrations and actions are playing a part.

"Although it did not come up in the conversation ... investors at Kinder Morgan have to be moved by the passion of British Columbians that are emerging in many dozens to be arrested on a daily basis, the determination of the Indigenous leaders here in British Columbia to protect the Burrard Inlet, the Salish Sea and the economy that depends on that," he said.

Kinder Morgan's move will be seen as a blow to Prime Minister Justin Trudeau, who has insisted the pipeline will be built. The expansion, which would triple the amount of oil flowing from Alberta to Burnaby, B.C., was approved by the federal government in 2016.

The company said it will consult with "various stakeholders'' to try and reach an agreement by May 31 that might allow the project to proceed, adding it needs "clarity'' on its ability to do construction in B.C. and protect its shareholders.

Kinder Morgan has spent about $1.1 billion on the $7.4-billion project so far.

Horgan said he spoke with Kinder Morgan president Ian Anderson, who told him the project has been "unnecessarily harassed'' by British Columbia.

"I told him I disagreed,'' Horgan said.

The B.C. premier said he also spoke to Trudeau and planned to speak to Alberta Premier Rachel Notley, but his position on the pipeline hasn't changed.

"I want to say to all Canadians that I profoundly believe in the rights of British Columbians to stand up and make sure that we're doing everything we can to protect the interests of our province,'' he said.

"I don't want to do that in a provocative way. I don't want any threats, I don't want any ultimatums and I believe other governments should follow suit.''

Horgan is pursuing a reference case in the courts to determine if his government can control the shipment of oil through the province on environmental grounds, which Kinder Morgan mentioned as a factor in its decision.

There is also a legal challenge in the Federal Court of Appeal, where the federal government's approval and B.C.'s environmental assessment certificate for the project are being challenged.

Environmental activist Tzeporah Berman is calling Sunday's announcement by Kinder Morgan the beginning of the end.

"Today is a very important day for B.C.," she said, "It shows that when we stand up, and there are moments in history when we have to stand up, that we can change the outcome and ensure the safety of our province and of our coast."

Meanwhile, B.C. Opposition leader Andrew Wilkinson said in a tweet that the B.C. NDP is engaged in a trade war with Alberta and confrontation with the federal government.

The federal and Alberta governments pushed Horgan to abandon his promise to do whatever his government can to stop the project.