Tensions are mounting in Boston, where 500 police are working to separate dozens of Free Speech Rally-goers from thousands of counter-protesters marching against hate.

Aerial video showed lines of police officers, some in riot gear and carrying billy-clubs, advancing to push back crowds in Boston Common.

By 2 p.m., the dozens who had gathered for the Free Speech Rally — who have publicly distanced themselves from the neo-Nazis and white supremacists of Charlottesville — had left the Commons.

It was unclear whether the protesters were disbanding or planned to rally elsewhere.

Earlier in the afternoon, there were numerous minor scuffles and shouting matches between the two sides.

Boisterous counter-protesters chased a man with a Trump campaign banner and cap, shouting and swearing at him.

Other counter-protesters quickly intervened on his behalf, helping the man safely over a fence to where the conservative rally was to be staged.

Nearby, a shoving match erupted between an American-flag-waving older woman and a counter-protester wearing the black garb of the “Antifa” anti-fascist group.

Video captured the black-clad protester then trying to run off with the flag as she clung to it and ran after him. She stumbled and fell to the ground, Fox News reported.

The Boston Free Speech Coalition, which organized Saturday’s rally, say they are opposed to the white supremacist message and violence that erupted a week ago in Charlottesville.

Saturday’s speaker roster had included Joe Biggs, formerly of the right-wing conspiracy website Infowars, and Kyle Chapman, a California activist accused of beating counter-protesters at a pro-Trump rally in Berkeley earlier this year.