Clashes erupted at a “Straight Pride” parade in Boston on Saturday when counter-protesters turned up in droves to oppose the event.

Boston Police Department spokesperson James Kenneally told HuffPost three dozen people were arrested on various charges, including disorderly conduct, unlawful possession of a dangerous weapon and assaulting officers.

According to the Boston Globe, about 600 counter-protesters met an estimated 200 marchers when the parade reached City Hall Plaza, where police barricades prevented protesters from accessing a concert stage where the Straight Pride rally was held.

The event featured floats and signs expressing messages of support for President Donald Trump such as “2020 Trump” and “Build The Wall.”

Ostensibly upset that city officials were protecting the marchers and permitting the parade, some protesters reportedly turned their anger towards the police towards end of the rally, prompting scuffles, arrests and the use of pepper spray.

People at the counter-protest event featured signs with a range of messages for the Straight Pride marchers, including “Oppressor cannot be oppressed,” “A straight pride parade is called TRAFFIC,” and “love is love and straight pride is hate pride.”

A Facebook event for the counter-protest, titled “Fight Supremacy: Hands Off Our Pride,” called the march organizers white supremacists ― a claim supported by multiple links between the organizers and far-right groups.

Rep. Alexandria Ocasio-Cortez (D-N.Y.) derided the event on Twitter, pointing out a clear lack of female representation at an event purported to promote being straight.