Thirteen people died when a US helicopter crashed near Baghdad Saturday, the US military announced in Iraq. The circumstances of the crash were as yet unknown and an investigation was underway, a spokesman said. The helicopter, which often transports civilians in addition to military personnel, crashed in an "explosive" region north-east of Baghdad which is inhabited by Sunnis, Shiites and Kurds, the CNN news network reported. However, US soldiers had been able to secure the crash site and seal it off.