The City of Boston and the FBI are investigating a disturbing march by a white supremacist group that took place over the weekend, with local leaders calling out hate speech but noting that much of what the group said is protected under the First Amendment, NBC Boston reported.

The Saturday march by Patriot Front did not result in any arrests, though several physical confrontations did occur.

Boston Mayor Michelle Wu told reporters that the city had no advance intelligence that the march was going to take place.

The city was inundated with calls to 911 as shocked residents witnessed the group marching through the streets.

Around 100 members of the group, with their faces covered, began demonstrating at 12:30 p.m. on Saturday near City Hall Plaza. Many of them showed up with shields.

"We know these threats are continuing to escalate across the country and that Boston must be the leading light in how we are acting in a coordinated way and protecting our community members," Wu said at Boston police headquarters.

According to the ADL, Patriot Front is a white supremacist group “whose members maintain that their ancestors conquered America and bequeathed it to them, and no one else” and that justifies its hateful ideology “under the guise of preserving the ethnic and cultural origins of its members’ European ancestors.”

The largest purveyor of white supremacist propaganda in the US, it largely spreads its message via the internet and also by distributing banners, flyers, posters and stickers.

Robert Trestan, director of New England's Anti-Defamation League, told NBC Boston that the group was known for spontaneous demonstrations.

"You don’t really know until they show up, so there are certainly some lessons to be learned if it happens again," Trestan said. "You also want to make sure that you’re not provoking a confrontation. So groups like this, they're looking for a provocation. Marches like this can be a form of intimidation."

Wu condemned the march on social media.

“The disgusting hate of white supremacists has no place here. Especially when so many of our rights are under attack, we will not normalize intimidation by bigots,” she tweeted. “As we mark Boston’s legacy as the cradle of liberty, we celebrate the continued fight to expand those liberties for all.”