Fox News has learned from sources who were on the ground in Benghazi that an urgent request from the CIA annex for military back-up during the attack on the U.S. Consulate and subsequent attack several hours later was denied by officials in the CIA chain of command -- who also told the CIA operators twice to "stand down" rather than help the ambassador's team when shots were heard at approximately 9:40 p.m. in Benghazi on Sept. 11.