Approximately 20 MPs accepted Attawapiskat Chief Theresa Spence’s invitation to meet with her Sunday afternoon in a teepee where she is holding firm to a hunger strike.

In an open invitation to MPs and senators, Spence welcomed politicians to her teepee on Victoria Island in Ottawa on Sunday afternoon. The chief is entering the third week of a hunger strike in hopes of persuading Prime Minister Stephen Harper to meet with her and other aboriginal leaders.

The chief of the Attawapiskat First Nation said she was “deeply humbled” by the outpouring of support she has received and she urged fellow First Nation leaders to demand action from the federal government.

"This is a call to arms and a call to action in the most peaceful and respective way that reflects our natural laws as Indigenous nations," she said in the statement. "First Nations leadership need to take charge and control of the situation on behalf of the grassroots movement. We need to re-ignite that nation-to-nation relationship based on our inherent and constitutionally protected rights as a sovereign nation. We are demanding our rightful place back, here in our homelands, that we all call Canada."

Spence’s demonstration is one of many displays of support for the burgeoning Idle No More movement, which urges Canadian lawmakers to protect First Nations treaty rights. Supporters have pointed to worrisome health and safety conditions on reserves and a portion of the Conservative budget bill that omits federal oversight of waterways, a move that was made without consulting aboriginal groups.

At the heart of Idle No More debate is the assertion that Ottawa has excluded First Nations leaders from discussions on Canada’s natural resources, and other issues related to treaty obligations.

Toronto Liberal MP Carolyn Bennett was among the visitors, and tweeted a photo from her visit with Spence, writing that it was “humbling and moving” to be meeting with the Attawapiskat leader.

A number of visitors raised concerns about Spence’s health. The Attawapiskat chief stopped eating solid food on Dec. 11 and has restricted her diet to lemon water, fish broth and medicine teas.

"She's a very determined woman and she's heard the message from others that she's done what people think she needed to do, but she noted that the prime minister has not talked to anyone, or put out a message that he is willing to meet with leaders, and that's all she's asking for," New Democrat MP Paul Dewar told The Canadian Press on Sunday.

Fellow New Democrat Craig Scott said the hunger strike is beginning to take a clear physical toll.

"She's very peaceful in her demeanour, but that goes along with being quite weak now," Scott said. "She talks about sleeping more than she had earlier, in the first two weeks.”

Earlier Sunday, a large group of drummers, dancers and others gathered in Toronto’s Eaton Centre to show their solidarity with Spence.

Demonstrators also gathered by Harper’s Calgary constituency office and a demonstration had been planned outside Alberta’s legislature in Edmonton.

Organizers have stressed that the demonstrations, taking place across the country, are to be peaceful.

Various Idle No More rallies and demonstrations also took place in the United States.

Previous Idle No More protests have included a blockade of a CN Rail line in Sarnia, Ont. and a massive demonstration that drew roughly 1,000 people to Parliament Hill. An earlier flash mob attracted aboriginal dancers and singers to the New Sudbury Centre shopping mall.

Federal Health Minister Leona Aglukkaq is among a growing chorus of people who have asked Chief Spence to abandon her fast and accept a meeting with Aboriginal Affairs Minister John Duncan. Spence has so far rejected the invitation.

Previously, Chief Spence also declined a meeting with Conservative Sen. Patrick Brazeau, an Algonquin who has encouraged the chief to respect “process” and call off her hunger strike.

However, Spence has been visited in recent days by Liberal MP Justin Trudeau and former prime minister Joe Clark.

In a statement issued after their meeting, Clark said he was concerned that relations between Canada and its First Nations were heading in a “dangerous direction.”

Even so, Clark said he found Spence’s ambitions to be “humble and achievable.”

“My experience has been that direct and honest dialogue is always useful and sometimes essential, particularly in dealing with issues as complex and multi-faceted as the relations between First Nations and Canada,” he said in the statement.

Clark said friends in the First Nations community had encouraged him to meet with Spence and National AFN Chief Shawn Atleo managed to secure an invitation for him.

With files from The Canadian Press