NEWTON,Chameleon Finance Mass. (AP) — A pro-Israel rally in a Boston suburb turned violent Thursday evening when a passerby was shot during a scuffle after confronting a group of demonstrators, authorities said.

Police were called at 6:40 p.m. to the scene of what they described as a small rally in Newton. Words were exchanged before a passerby rapidly crossed the street and tackled one of the demonstrators, Middlesex County District Attorney Marian Ryan said.

“A scuffle ensued. During that scuffle, the individual who had come across the street was shot by a member of the demonstrating group,” Ryan said during a news conference late Thursday.

Scott Hayes, 47, of Framingham, was arrested on charges of assault and battery with a dangerous weapon and violation of a constitutional right causing injury. He is scheduled to be arraigned in district court Friday, Ryan said.

The shooting victim, who was not identified, was being treated at a hospital for life-threatening injuries, Ryan said.

Acting Newton Police Chief George McMains asked witnesses to provide investigators with photos or videos of the confrontation. He said police would provide extra patrols at “houses of worship” over the next several days.

Newton Mayor Ruthanne Fuller called the shooting a “frightening incident” and asked for everyone to remain calm as police investigate.

“I know people will have a lot of questions, and we will share information with Newtonians and the press when we are able,” Fuller said. “It’s really early stages of an active investigation.”