U.S. Defense Secretary Ash Carter has arrived on a surprise visit to Afghanistan to meet with U.S. troops and Afghan officials.
Carter's visit on December 18 comes as Afghanistan faces security setbacks, with the Taliban staging more attacks and inflicting more casualties on Afghan forces in the last year compared to previously.
In a report to the U.S. Congress released this week, the Pentagon said there were 27 percent more high-profile attacks in the capital city of Kabul from the beginning of the year to mid-November, compared with the same period last year.
Afghan national defense and security forces also had 27 percent more casualties from the start of 2015 up to mid-November compared with the same period last year, the Pentagon report said.
U.S. President Barack Obama said in October he will prolong the U.S. military engagement in Afghanistan by maintaining a force of 9,800 troops there through most of 2016.