NEW : four of the wounded are German . Kabul , Afghanistan ( CNN ) -- The top Afghanistan commander arrives in U.S. on A year ago of more violence . Attack serves as reminder of a brazen insurgency , ISAF says . Pre-dawn attack targets subcontractor of U.S. aid agency .
NEW : four of the wounded are German . The top Afghanistan commander arrives in U.S. on A year ago of more violence . Attack serves as reminder of a brazen insurgency , ISAF says . Pre-dawn attack targets subcontractor of U.S. aid agency .