US officials say insurgents attacked four Iraqi police stations in Baghdad during what's been a string of attacks in several cities. The insurgents in Baghdad used mortars, hand grenades and assault rifles. A US statement says Iraqi police fought back, and defended the stations with little assistance from coalition forces. The series of attacks across Iraq killed dozens of Iraqis and three US soldiers. Dozens of people are injured. A curfew has been imposed in Mosul, and people are being urged to stay at home.