A secret video showing US air crew falsely claiming to have encountered a firefight in Baghdad and then laughing at the dead after launching an air strike that killed a dozen people, including two Iraqis working for Reuters news agency, was revealed by Wikileaks today. The footage of the July 2007 attack was made public in a move that will further anger the Pentagon, which has drawn up a report identifying the whistleblower website as a threat to national security. The US defence department was embarrassed when that confidential report appeared on the Wikileaks site last month alongside a slew of military documents. Less