One week after a white supremacist demonstration in Charlottesville, Virginia left one woman dead, thousands of people marched through the streets of Boston on Saturday to protest a rally staged by conservative activists.

Protesters chanted anti-Nazi slogans and waved signs that condemned white supremacy as they marched towards the city's historic Boston Commons park where a "Free Speech Rally" was being held. One woman who attended the protest posted a video on Twitter showing hundreds of people gathering for the march.

Counter-protesters also scuffled with security forces during their rally. Later, members of the Black Lives Matter joined the protest and burned a Confederate flag.

One man held a sign that read: "Stop pretending your racism is patriotism," while another woman's sign read: "Muslims welcome, racists out."

Boston police estimated that the number of people protesting the rally at about 15,000. That number dwarfed the several dozen people who attended the conservative rally, which ended roughly an hour and half after it began, according to police. At least 27 people have been arrested, said Boston's Police Commissioner William Evans. He added that the arrests were mostly for disorderly conduction, while some were for assault and battery.

Evans said on Friday that 500 officers - some of whom are undercover - have been deployed to keep the two groups apart. Police placed barricades around the park to prevent vehicles from entering. They also built a cordon on the site of the rally to keep the two groups separated.

Read more: What are the links between US and German neo-Nazis?

Conflicting rallies

The rally's organizers have publicly denounced the neo-Nazi and white supremacist groups that were present in the Charlotte violence and said their event would be peaceful. Others objected to the event's right-wing speakers and feared that white nationalists might show up anyway.

One of the scheduled speakers, Kyle Chapman, claimed allegiance to a group called the "Fraternal Order of Alt-Knights," which is described by the Southern Poverty Law Center as a "new Alt-Right group of street fighters."

Television footage showed a group of counter-protesters chasing a man with a Trump hat, but other counter-protesters intervened and helped the man over the fence into the area where the rally was to take place.

Other protesters wearing black also grabbed an American flag out from an elderly woman and she stumbled and fell to the ground.

The conservative rally's permit came with severe restrictions, including a ban on sticks and anything that could be used as a weapon.

Read more: White supremacy and neo-Nazis in the US - what you need to know

Nationwide protests

The march in Boston was the first large and racially-charged protest in a major US city since Charlottesville. Last weekend, a woman was killed after a white supremacist rammed his car into a group of counter-protesters in the Virginian city, wounding scores of others.

Neo-Nazis and white supremacists converged in Charlottesville to protest the planned removal of a statue of Robert E. Lee, who led the pro-slavery Confederacy army during the US Civil War, which ended in 1865.

US President Donald Trump's lackluster response to the violence prompted outcry around the world and from both Republicans and Democrats, who criticized him for not immediately condemning the white nationalists. He also blamed "both sides" for the violence.

Other demonstrations are also expected to take place on Saturday in other major US cities, including Atlanta, Dallas and New Orleans.

ls,rs/rc  (AP, AFP, Reuters, dpa)