An undated picture received Dec 8, 2011 shows a US RQ-170 unmanned spy plane displayed in front of a flag with Persian script that reads "Down with the US (top), down with Israel and down with Britain (bottom)" at an unknown location in Iran. The unmanned US drone Iran said on Sunday it had captured was programmed to automatically return to base even if its data link was lost, one key reason that US officials say the drone likely malfunctioned and was not downed by Iranian electronic warfare. [Photo/Xinhua]