Japan's National Police Agency has disclosed photos of 13 people suspected of involvement in "special frauds," or complex schemes to swindle strangers.

Four of the 13 are on the police's wanted list, while the other nine remain unidentified.

They are believed to have illegally obtained cash cards from victims to withdraw their cash from ATMs as part of a fraud ring.

The agency says damage from special fraud cases last year totaled 28.1 billion yen, or about 190 million dollars, nationwide.

This year, more than 12,000 cases were reported through September, with damage totaling 24.6 billion yen, or some 166 million dollars.

Refund scams top the list of fraud cases at some 3,200, followed by impersonation of close relatives over the phone, and tricking victims into handing over their cash cards.

The suspects' photos were released on Wednesday on the websites of the National Police Agency, the Tokyo Metropolitan Police and prefectural police in Chiba, Niigata and Osaka.

Police hope that asking the public for information about the suspects could lead to their arrests and prevent further damage.