The group gathered on Market Street just before 8 p.m., the department told Daily Voice. "The number" of people in the crowd "has not been confirmed; however, it is safe to say a few hundred," police wrote.
A single officer received "non-life-threatening" injuries at the scene and "three to four" arrests were made, officials said.
In a statement just after 10 p.m., Mayor Jim Kenney described the crowd as "dangerous" and said such "behavior will not be tolerated."
"I’m saddened when young people engage in behavior that endangers themselves and others, especially because it is not representative of the majority of our city's youth, who are positively engaged in their communities," the mayor added.
Police have not identified the people arrested at the scene.
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