The Medecins sans Frontieres aid group is to pull out of Afghanistan after more than 20 years due to security concerns and lack of progress in an investigation into the killing of five staff, a spokeswoman said July 28, 2004. Afghan staff of Medecins sans Frontieres (MSF) in Afghanistan stand at the MSF compound gates in this file photo taken in Kabul June 3, 2004.    REUTERS/Ahmad Masood/File Photo