SEATTLE (AP) — Authorities in Seattle say three police officers were injured and 18 people were arrested as the result of a riot involving explosives, bottles and rocks. Police say in a news release that the violence erupted during a protest Sunday night against the Seattle Police Officers Guild. Someone set off a large explosive and attempted to break the window of a police vehicle. Bottles, rocks and fireworks were reportedly thrown at officers after the crowd was ordered to disperse. One of the three injured officers was hospitalized. Police say blast balls and pepper spray were used to disperse the crowd.