Erie County Executive Mark Poloncarz said video of the incident "sickens me."
Dermot Shea said protesters were not seriously injured, but officers have been shot at, stabbed and otherwise assaulted.
Hundreds marched across the Brooklyn Bridge in New York City in a massive show of mourning for Floyd, who died May 25 while in Minneapolis police custody.
NBC News' Craig Melvin speaks to The Breakfast Club's Charlamagne Tha God about the ongoing protests over George Floyd's death and why he believes the multicultural protesters are signs of a "paradigm shift."
Hundreds of protesters have taken to the streets to call for police reform after the death of George Floyd in police custody. NBC News' Blayne Alexander reports.