Boston has granted permission for an event that organizers are calling a free speech rally but that some people fear is actually a white nationalist rally similar to the one that erupted in violence in Virginia last weekend.
The permit for Saturday's event on Boston Common comes with severe restrictions, including a ban on backpacks, sticks and anything that could be used as a weapon.
Barriers will separate participants from a planned counterprotest that its organizers are calling a "racial justice solidarity march."
"We don't want a repeat of what happened in Charlottesville," Boston Police Commissioner William Evans said. "Boston is too united. We have a city that doesn't tolerate hatred and bigotry, and we wanted to make it clear to both groups."
A woman was killed Saturday in Charlottesville when a car plowed into counterprotesters at a Unite the Right rally attended by neo-Nazis and white supremacists.
Boston Mayor Marty Walsh said the city will do what is necessary to head off violence initiated by either side.
"We are going to have a zero-tolerance policy," the Democratic mayor said. "If anyone gets out of control -- at all -- it will be shut down."
He said in a separate interview that he does not expect violence.
The permit granted Wednesday is for 100 people and a two-hour rally from noon until 2 p.m., with a two-hour setup and an hour-long breakdown time.
John Medlar of the Boston Free Speech Coalition thinks as many as 1,000 people could show up.
"There's a lot of variables we simply can't account for -- will the extra controversy drive people away or make it even more popular?" he said.
The group said on Facebook that it is not affiliated with the Charlottesville rally organizers in any way.
"We are not associated with any alt-right or white supremacist groups we are strictly about free speech," the group said.
Christopher Cantwell, a self-described white nationalist who attended the rally in Charlottesville, told The Associated Press on Thursday that he was contacted by a member of the FBI's Joint Terrorism Task Force about helping defuse any violence in Boston. He said he knew of no plans for anyone attending the rally to ferment violence but they would defend themselves if attacked.
"He wanted to avoid that rally from turning into another Charlottesville," Cantwell said of the task force member. "I told him I don't know who is organizing the Boston rally but that if I found out anybody on the al-right was planning on initiating force against anybody that I would absolutely tell him.
"Every alt-right rally I've been aware of or I've been part of, the people go there prepared to use force to defend themselves if necessary because people attack us," he said.
Cantwell, who lives in Keene, New Hampshire, said he can't attend the Boston rally due to what he said were outstanding legal issues stemming from violence he was involved in during the Charlottesville rally.
"I wouldn't go anyway because I can't carry a gun in Boston and people want to hurt me," he said.
Associated Press writer Michael Casey in Concord, New Hampshire, contributed to this report.