PORTLAND – Dozens of people pressing for rights for illegal immigrants gathered for a peaceful demonstration Monday just minutes after a counterprotester was bloodied by a teenager who hid his face with a bandanna.

The attacker, described as a Hispanic teenager, went after one of three white people carrying signs arguing that illegals have no rights, police said.

As the teen fled, the victim dropped to the pavement after being hit with something heavy that the teen had carried, possibly in a sock or a bandanna, said Portland police Sgt. Robin Gauvin. There were no arrests as of late afternoon.

The victim, identified as Robert Gorman, 23, of Portland, was taken away in an ambulance minutes before 200 people gathered. He was treated at Maine Medical Center and released.

“When you promote violence, you get violence,” said the Rev. Virginia Maria Rincon, one of the organizers. “Our rally is about promoting a peaceful dialogue.”

About 200 people gathered at Monument Square to voice support for reforms that would legalize undocumented immigrants. The rally was one of many across the country on Sunday and Monday calling for Congress to promote immigrants’ rights.

One of the organizers, Portland lawyer Rafael Galvez, said people won’t forget how members of Congress vote. “They will be remembered for how they vote on this sensitive issue. They can be compassionate, or cruel,” Galvez said.

The demonstrators of all colors carried signs and chanted. “This is our America. This is what America looks like,” Shenna Bellows, executive director of the Maine Civil Liberties Union, said through a bullhorn to the cheering crowd.

Not everyone agreed with the majority view. Jonathan Talbot of Portland said he supported the views of the man who was assaulted.

“I think we should enforce the laws we have. Then we go from there to decide what we want to do to assimilate these people into society,” Talbot said. He described the Border Patrol’s efforts as a “catch-and-release” program.