Prosecutors say 31-year-old Milford resident Jesse Osmun molested children as young as 5 last year and this year. They say the girls called him "uncle" and claim he gave them candy for performing oral sex.
A criminal complaint says a teacher saw Osmun zip up his pants in a preschool toy room with three girls.
Osmun was arrested Thursday and was charged with engaging in illicit sexual conduct in foreign places. He didn't enter a plea. His attorney won't comment.
Peace Corps volunteers travel to developing nations to help on issues such as health education. A Peace Corps representative wouldn't comment.
Osmun quit the Peace Corps in May.