SLIDESHOW: Photos of Iraqi military gear claimed by ISIS in Ramadi

  Some 8,000 people have fled the embattled streets of Ramadi as thousands of ISIS fighters seized the key Iraqi city, killing 500, and reportedly going door-to-door looking for Iraqi government troops and police to run out of town.   Although there were a large number of Iraqi security forces occupying Ramadi, most troops fled after ISIS fighters began their assault on the city center Sunday, leaving behind Humvees and armored vehicles supplied by the U.S. military, a separate senior U.S. military official told Fox News.   U.S. equipment fell into ISIS hands when Iraqi troops fled, Pentagon spokesman Col Steve Warren confirmed Monday.   An ISIS Tumblr account posted a series of photos Monday of vehicles, including Humvees and explosive-resistant tanks claimed by ISIS after the Iraqi Army retreated.