More than 61 people in the United States -- 170 people around the world -- have been arrested in a child porn sting, according to officials.

11 U.S. girls, ages 3 to 13, were rescued after being sexually abused by child pornography producers. Dozens more were found in Europe.

The investigation, code-named Operation Koala in Europe, began when investigators discovered a pornographic video found in Australia had been produced in Belgium.