A gunman has opened fire in the Fort Hood US Army base area in central Texas, injuring an unknown number of people, with casualties being reported.<br /><br />People at the base have been told to close doors and stay away from windows.<br /><br />Fort Hood was the scene of a mass shooting in 2009 when 13 people were killed.<br /><br />Al Jazeera's Rosiland Jordan is live from Washington DC.
