Denver firefighters battled a second-floor apartment blaze of uncertain origin, rescuing several trapped residents after others jumped. Denver Health Medical Center ambulances carried "multiple injured parties" for treatment, Denver Fire Department spokesman Lt. Ahmid Nunn said. Denver Health nurses said as many as 10 ambulances carried fire victims to the emergency room Sunday night. The fire broke out shortly before 9:14 p.m. at the Federal View Apartments, 2625 Federal Boulevard. Several streets were blocked off in the area as crews battled the blaze.