Milwaukee’s mayor and police chief on Tuesday pleaded with citizens and lawmakers to help address ongoing gun violence punctuated by shootings outside an NBA playoff game that left 21 injured.

Police Chief Jeffrey Norman said police have arrested 11 people varying in ages from 19 to 30 for the Friday night incidents near a downtown entertainment area known as the Deer District. Two of those arrested have been identified as shooters. Nine of the 11 guns that were recovered were fired that night, Norman said at a news conference.

Three people were killed in separate shootings around the city the following night.

Norman said police will be deploying additional officers and resources and will be enforcing a curfew already on the books for youth ages 17 and under. He said violence will not be the “new normalcy” and asked the community to help.

“Our path forward to a safer Milwaukee requires that everybody join together in partnerships,” Norman said. “Standing on the sideline is not an option.”