NEW : NATO said the attacker struck as forces were walking toward a park . 20 Afghans dead , Six were wounded , the provincial governor said . Three Afghans troops were wounded , the governor said . The attack took place in a Maymana market .
NEW : Taliban said the attacker struck as forces were walking toward a park . Six Afghans dead , 20 were wounded , the provincial governor said . Three American troops were wounded , the governor said . The attack took place in a Faryab province market .