Three of the victims were US troops who were taking pictures , despite previous warnings by Afghan forces not to wander around the city .
A suicide bomber attacked a group of people in a park in Afghanistan 's northern Faryab Province , killing at least 10 .
Three of the victims were US troops who were taking pictures , despite previous warnings by Afghanistan forces not to wander around the city .
A suicide bomber attacked a group of people in a park in Afghanistan 's northern Faryab Province , killing at least 10 .