Sgt. Stephen Vinansky says residents reopened a fire hydrant in Pittsburgh's East Hill neighborhood on Sunday after firefighters had already closed it.
He says when a private security organization arrived to close the hydrant a second time, youths threw objects, including bricks, at their vehicles. Vinansky says scores of residents poured into the streets. Police used pepper spray to clear the crowd.
Residents deny throwing anything but water. They say police overreacted.
Vinansky says the five people arrested have been charged with disorderly conduct and resisting arrest.