As thousands marched through Boston Saturday to call for stricter gun control laws and an end to an epidemic of gun violence, several dozen counterprotesters rallied to oppose what they see as a push to limit individual freedoms and trample on constitutionally guaranteed gun rights.

Organized online by the group Resist Marxism, the demonstration that gathered on Beacon Street in front of the State House around 11 a.m. and later continued onto Boston Common featured no organized speeches, but participants spoke passionately with each other and their opponents about defending gun rights from a movement they see as misguided and misinformed.

“March for Our Lives has a lot of money behind them; they have a lot of politicians behind them,” said Mark Sahady, 42, a demonstration organizer with Resist Marxism.

The students involved in the march “are being used as pawns by the media and the political class,” he said.

Draped in an American flag, 53-year-old Bill Bachant of Lakeville said he fears that any move to tighten gun control laws could lead to a wider restriction of personal freedom.

“It’s not going to stop at assault rifles; it’s going to be everything,” he said.

“The ironic thing is I’m here to preserve those people’s rights to defend themselves and their family,” Bachant said, as those opposed to the pro-gun rally chanted “Shame!” and “No KKK, No Fascists-USA, No Trump,” at the demonstrators.

A line of Boston police officers with bicycles moved in to stand between the two sides. Around 11:30 a.m., the pro-gun demonstrators began moving into Boston Common, where many had gathered to join the March for Our Lives protest.

Police surrounded the demonstrators as they moved through the Common. A group of people affiliated with the March for Our Lives, wearing pink vests and calling themselves “peacekeepers,” formed a ring around the demonstration as it slowly inched forward.

Members of the group Veterans for Peace also stood between the two sides.

“We have to help maintain the peace. Both sides can get overheated, and we try to prevent that,” said Jeff Brummer, 73, a member of Veterans for Peace who was holding one corner of a large white flag emblazoned with his group’s name and a dove. “Clearly these anti-Marxist types are trying to provoke those around to attack.”

The demonstrators stopped atop a hill at the center of the Common, where they were quickly outnumbered by gun control advocates.

The crowd around the demonstrators grew even larger as marchers who had begun their day at Madison Park Technical Vocational High School in Roxbury arrived carrying signs that said “How many more?” and “The time is now.”

Though most of the pro-Second Amendment demonstrators were adults, a few teenagers were scattered throughout.

T.J. McDonald, 17, a junior at Blue Hills Regional Technical School in Canton, said she came to the protest to proudly exclaim her opposition to gun control — a position that she says earns her ridicule from her classmates.

“A lot of [the time in] high school, they say they’re teaching you how to think, but they’re teaching you what to think,” she said.

Mike Moura, 24, a Resist Marxism spokesman from Stoughton, said the group had planned to move closer to the stage that March for Our Lives demonstrators had set up by Beacon Street, in an effort to “mix with the crowd and have a civil debate about gun control.”

But rhetoric between the two sides became heated, with people hurling insults and curse words across the police barrier, and one demonstrator with a megaphone deriding the opposing side as “violent Commies.”

Officers repeatedly asked the pro-gun demonstrators to leave the Common but did not order them out, Sahady said.

The demonstrators began moving out of the Common shortly after 2:15 p.m., escorted by police.

“I didn’t want to keep arguing with the police for another two hours,” Sahady said. “They feared people would get violent.”

The demonstrators marched to the State House steps, where their day had begun, but by then the group had dwindled to about two dozen.

Still, organizers said they felt they had gotten their message across.

“I think we definitely demonstrated that there’s people in Boston who stand up for the Second Amendment,” Sahady said.

The group is in the beginning stages of planning another rally to oppose gun control on June 2, he said.

Jacob Carozza can be reached at jacob.carozza@globe.com.