US Defence Secretary Ashton Carter addresses a joint press conference with Afghan President Ashraf Ghani at the Presidential Palace in Kabul on July 12, 2016. US Defence Secretary Ashton Carter reiterated Washington's support for "courageous" Afghan security forces July 12, days after the United States and NATO pledged to keep thousands of troops in the troubled country. / AFP PHOTO / SHAH MARAISHAH MARAI/AFP/Getty Images