US Secretary of Defense Chuck Hagel (centre) poses for a picture with US troops at Kabul airport on March 11, 2013 before boarding a flight back to Washington. The US commander in Afghanistan has ... more 

US Secretary of Defense Chuck Hagel (centre) poses for a picture with US troops at Kabul airport on March 11, 2013 before boarding a flight back to Washington. The US commander in Afghanistan has warned troops that they face an increased threat of attack after a series of inflammatory anti-US comments by President Hamid Karzai less