Japan saw a record number of child pornography cases last year, reflecting a crackdown made possible when police acquired a massive list of child porn buyers that included teachers and politicians.

A National Police Agency report released earlier this month said police arrested or referred to prosecutors 1,703 people involved in a record 2,413 cases, up 316 from the year before.

"Japan's child pornography issue is notorious worldwide," a senior investigator said. "Because there is demand, there are victims, so we need to thoroughly clamp down on the crime."