Democratic Sens. Elizabeth Warren of Massachusetts and Amy Klobuchar of Minnesota are confirmed to join six other candidates at the first-ever Frank LaMere Native American Presidential Forum in Sioux City, Iowa, later this month.

The forum will be focused on the concerns of Native Americans and is being hosted by the voting rights organization Four Directions. It is planned for Aug. 19 and 20 at the Orpheum Theatre in Sioux City.

Sen. Bernie Sanders of Vermont, author Marianne Williamson, Montana Gov. Steve Bullock, former U.S. Secretary of Housing and Urban Development Julian Castro, former Rep. John Delaney of Maryland and Independent candidate Mark Charles, a member of the Navajo Nation, were previously confirmed.

“No candidate should take the Native American vote for granted,” O.J. Semans, co-executive director of Four Directions, said in a news release. “But when candidates demonstrate they understand our issues and will work for the betterment of our people and our communities, they can earn our votes.”

Discussions continue with other campaigns and additional candidates are expected, according to Four Directions, which said all presidential candidates were invited to participate.

Representatives of tribes and Native American organizations from across the country will serve on panels posing questions to the candidates, according to Four Directions. The forum will be live streamed.

“We know candidates will be in Iowa for the State Fair just before our forum or at the Iowa AFL-CIO state convention the day after the forum," Semans said. "We hope the next president will find time to attend the Forum. No doubt Iowa will be watching, but more important, this event is an historic opportunity to address millions of Native Americans.”

Co-hosts for the event include: Native Organizers Alliance, National Congress of American Indians, Native American Rights Fund, Great Plains Tribal Chairman’s Association, Coalition of Large Tribes, Midwest Alliance of Sovereign Tribes, United South and Eastern Tribes, Rocky Mountain Tribal Leaders Council, Global Indigenous Council and Seeding Sovereignty.