It happened amid Saturday's "Blue Lives Matter" march in Center City.
Police say about 75 protesters identifying themselves as part of anti-fascist or "antifa" groups were protesting near City Hall at about 11:30 a.m. Saturday.
Several members began to fight with police, according to authorities.
A total of 16 people were arrested, nine of whom were issued citations for failure to disperse and seven of whom charged with misdemeanor disorderly conduct.
Police said the "Blue Lives Matter" march was occurring simultaneously, but the two groups didn't interact.
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