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A social media campaign calling for a boycott of Saturday's Women's March on Philadelphia is quickly spreading. Its rationale? The march organizers' perceived collaboration with police.

"The Women's March of Philadelphia thinks it's OK to collaborate with the police department to set up security checkpoints and conduct random searches on march attendees, ostensibly stopping and frisking them, putting those already targeted by law enforcement at an even greater risk," reads a message that started spreading on Facebook Wednesday. "Forget that. Don't attend the Women's March."

People sharing the message on social media are asking friends to share it further. While it’s unclear who started the campaign, its message gained steam after it was shared by activists with large social media followings, including George Ciccariello-Maher, an outspoken ex-Drexel University professor known for his controversial tweets, who has more than 6,000 people following him on Facebook.

Johanna James, a black woman and an organizer with a local group that advocates for people of color, transgender women and other marginalized groups, attended last year's Women's March on Philadelphia, but won't be going Saturday because of the police presence, which she said invites "trauma on our already traumatized people."

"One of the biggest antagonizers of the black community, specifically, is the police," said James, a co-organizer with the Womanist Working Collective. "Inviting them into that space ultimately means you're not taking our feelings concerning them into any sort of consideration."

Other organizations have said they're no longer supporting the event, including the Philadelphia-based Women's Medical Fund, a nonprofit that aims to expand abortion access for low-income people. Executive director Elicia Gonzales said staff members decided Friday they would not be part of the demonstration after hearing from people in communities they serve who were "saying that they didn't feel welcomed or reflected by the march."

"We didn't take this decision lightly and really thought about all the ramifications of both walking and not walking," she said, "but we stand by our decision."

The boycott campaign began after Women's March organizers indicated on the event's Facebook page that attendees will be subject to search by police.

"Due to the projected size and scope of the 2018 Women's March on Philadelphia on January 20th, 2018, the City will be implementing some additional security measures in order to ensure the safety of all in attendance," according to the Facebook page. The organizers listed prohibited items, including weapons, fireworks, drones and "illegal or illicit substances of any kind."

Organizers are expecting more than 50,000 people to march on the Benjamin Franklin Parkway on the one-year anniversary of President Trump's inauguration.

In response to questions about the boycott campaign, Philly Women Rally, the committee behind the Women's March, released a statement Thursday morning directing all inquiries regarding safety and security to the city. The statement did not directly address the boycott campaign.

"The City of Philadelphia and the Philadelphia Police Department are committed to facilitating and protecting the First Amendment rights of all citizens, regardless of race, cultural background, age, gender identity and sexual orientation," city spokeswoman Ajeenah Amir said in a statement. "For the safety of all in attendance, event-goers can expect to encounter security protocols similar to those in place at other large-scale outdoor events, concerts, festivals, etc. In no way will the Philadelphia Police Department, or any other city agency, limit the ability of attendees to lawfully and peacefully participate in this event."

Deputy Police Commissioner Dennis Wilson said rumors that police would be "stopping and frisking" attendees were not accurate, adding: "We're not infringing on anyone's First Amendment rights in any way."

The protocols are not dissimilar to those in place during the NFL draft in April. When the city played host to the draft, police set up a secure perimeter around the event and established multiple security checkpoints.

City officials say they have been working with Philly Women Rally to establish safety protocols. The event is being evaluated based on its location, projected attendance, timing, traffic hazards and potential threats of violence or terrorism.

Gwen Snyder, a longtime Philadelphia activist and organizer who is white, said she attended last year's Women's March on Philadelphia, but won't be attending Saturday, citing "distrust in some communities of color around police presence in general." She said that of dozens of protests she's organized over the last two decades — including a 6,000-person "Tax March" last April — she's never worked with police to set up security checkpoints.

"I think it sets a dangerous precedent," Snyder, 32, said. "Today it might be they're searching folks for knives and spray paint. But if they're doing that, it's just as likely it becomes the norm for protesters to be searched."