OTTAWA -- Dozens of protesters delayed an appearance by the prime minister Tuesday afternoon, drumming and chanting in a government building where Justin Trudeau was set to speak.

Police kept the prime minister out of a Sussex Drive building in Ottawa, where he was to address a forum bringing together federal officials and representatives from self-governing First Nations that have "modern" treaties with the Crown.

Trudeau's address was moved to another government building close to Parliament Hill.

"In this government, you have a partner willing to figure out the path forward that is right for each of you, and eventually right for every Indigenous person in this country," Trudeau said. "It's not going to be easy. It's not going to be done quickly."

But Trudeau said the leadership exemplified by those gathered at the forum gave him confidence in what can be accomplished in the coming years.

The protesters expressed anger about the RCMP's intervention in a blockade in northern British Columbia, enforcing an injunction from the B.C. Supreme Court.

The injunction is to remove anyone who interferes with a Coastal GasLink pipeline project in and around the Morice River Bridge.

Members of the Gidimt'en clan of the Wet'suwet'en First Nation have set up a camp and a checkpoint southwest of Houston, B.C., on a forest-service road that leads to a pipeline construction site.

Coastal GasLink says it has signed agreements with all First Nations along the route but demonstrators say Wet'suwet'en house chiefs, who are hereditary rather than elected, have not given consent.

The federal NDP's reconciliation critic said Tuesday the justification used for the RCMP's intervention is "pretty lame" in an era of supposed reconciliation with Indigenous Peoples.

Romeo Saganash joined demonstrators on Parliament Hill before the group marched through downtown Ottawa streets with signs including a large red one reading: "RCMP Off Wet'suwet'en Land."

Saganash said he did not hear back from the provincial and federal Indigenous-affairs ministers he asked to help alleviate tension in northern B.C. prior to the arrests by the Mounties.

Public Safety Minister Ralph Goodale's office repeated its previous remarks on Tuesday, saying the federal government is committed to a renewed relationship with Indigenous peoples based on the recognition of rights, respect, co-operation, and partnership.

"The RCMP respects and protects the right to peaceful demonstrations as guaranteed under the Canadian Charter of Rights and Freedoms," it said.