The gang is notorious for kidnapping groups of people for ransom.
The same gang, 400 Mazowo, abducted a group of Catholic clergy in April.
The clergy were later released but it is not clear if a ransom was paid.
Who are the victims?
All of those kidnapped are US citizens, except one who is a Canadian national.
Among those seized are five men, seven women and five children. The youngest child is reportedly only two years old.