In a Sept. 23 letter addressed to Oregon politicians, 30 civil rights groups and labor unions demanded they take concrete action ahead of Saturday's planned Proud Boys rally in Delta Park.

"As we look ahead to the planned rally by paramilitary and alt-right figures on September 26th in Portland, we are reaching out to ask you—the elected and appointed  leaders with the authority and responsibility to keep our community safe—to renew your commitment and take additional steps to create lasting change," the letter says. "By using Portland as a place to hone their paramilitary training and garner the media attention they need to promote themselves, alt-right and paramilitary groups are now working  to build power around the region, chill democratic practice, threaten community safety, and undermine civil society."

Ahead of Saturday's rally, some observers anticipate that it could erupt in more political violence.

The Proud Boys, the right-wing group holding the rally, said in its application for a city permit that it is demonstrating in support of Aaron J. Danielson, a Trump supporter killed by a Portland anti-fascist, and Kyle Rittenhouse, the suspect in a Kenosha, Wis., double homicide. The group's language suggests it seeks revenge.

"Portland leadership is unwilling to stop the violence," organizer Enrique Tarrio wrote. "They have been blinded by their hatred of our President and will not allow outside help stopping the violence. We the People are going to gather at Delta Park against Antifa Terrorists."

Today's letter, sent out by the civil rights group Western States Center, which tracks extremism in the Pacific Northwest, was co-signed by 29 local groups including Planned Parenthood Advocates of Oregon, Service Employees International Union Locals 49 and 503, Oregon AFCSME Women's Committee, Oregon Justice Resource Center, and Oregon Jewish Museum and Center for Holocaust Education.

The co-signers listed four specific demands for officials: (1) coordination between the Portland Police Bureau, Multnomah County District Attorney's Office and other law enforcement agencies to protect community safety, (2) a joint statement of solidarity against hate and violence, (3) a commitment from law enforcement to avoid bias in policing and intervene if violence erupts, and (4) a visible display of the community's commitment against hate.

"City leaders must make clear that they will not allow Portland to be used as the battleground  for a war by proxy. Portland must be united in saying: Not in our town. Not anywhere," the letter says. "While paramilitary and alt-right actions in Portland are often amplified as a form of spectacle, we know that their track record also includes countless instances of assault and intimidation."

The letter was delivered via email Wednesday to the recipients, who include Gov. Kate Brown, Senate President Peter Courtney, House Speaker Tina Kotek, Attorney General Ellen Rosenblum, Oregon State Police Superintendent Travis Hampton, Multnomah County District Attorney Mike Schmidt, Portland Mayor Ted Wheeler, Portland Police Chief Chuck Lovell, and Portland City Commissioners Amanda Fritz, Chloe Eudaly, Jo Ann Hardesty and Dan Ryan.

In an op-ed published Thursday in the Portland Tribune, Wheeler decried Saturday's rally, telling the conservative extremist activists "they are not welcome here."

"While espousing patriotism and a commitment to peaceful protest, some in these groups and many who associate with them have a record of racism, intolerance and hate," Wheeler wrote. "Those are not Portland values, and they are not welcome. Hate has no home in Portland. Violence has no home in Portland. Anyone intending to intimidate, create fear, commit violence, or spread hate is not welcome here."