Canada's National Energy Board (NEB) canceled the first day of hearings on TransCanada Corp.'s proposed Energy East Pipeline in Montreal on Aug. 29 after protesters disrupted the panel session, an agency spokeswoman said.

Montreal police said three protesters were arrested on obstruction charges, with two of the three also charged with assaulting a police officer.

Footage posted on Twitter by local media showed protesters at the venue standing, clapping and chanting at the panel. TV pictures also showed one man rushing toward the table at which the panel was seated, while shouting before being grabbed by security guards.

Environmental groups opposed to Canadian oil sands development have fought the 1.1 million barrel per day Energy East Pipeline, which would carry crude oil from Alberta to Canada's Atlantic coast.

Opposition has been particularly strong in the French-speaking province of Quebec, which the pipeline would need to cross on its way to the coast. Opponents include Montreal Mayor Denis Coderre Denis Coderre, who has cited concerns the route could endanger forest and agricultural land.

There is no word yet on a new date for the hearing, said NEB spokeswoman Sarah Kiley.

"Disruptions prevent intervenors from sharing their views and asking their questions," the regulator said in a statement. "Disruptions and disrespectful behavior are not acceptable."

Montreal police could not immediately provide details about whether the protesters came from a specific activist group.

TransCanada spokesman Tim Duboyce said the company was awaiting further instructions from the NEB on how the hearings will proceed.

"We are standing by and ready to respectfully and constructively begin the sessions in Montreal after five such productive sessions in New Brunswick--and we will be ready when the sessions resume," TransCanada said in a statement.

Calgary-based TransCanada also proposed building the controversial Keystone XL Pipeline, which was denied a U.S. presidential permit by President Barack Obama last year, and is a frequent target of environmental protesters.

Marc-Andre Gosselin, a spokesman for Coderre, said Montreal officials were also waiting to get more information about when the hearings will resume.

Energy East has had several setbacks in Quebec. In March, the provincial government filed an injunction against the pipeline to force an environmental review, which TransCanada later agreed to.

Last November, TransCanada scrapped plans to build a marine crude oil export terminal in Quebec after environmentalists raised concerns about the terminal's impact on beluga whales in the St. Lawrence River.