UFJ Bank said Tuesday that hidden cameras have been found at several automated teller machines in the Tokyo metropolitan area, apparently to record people entering their personal identification numbers.
The cameras may have photographed some PIN numbers, but no one has reported money stolen.
A security guard found a camera in early September inside a leaflet box the size of a business card placed at eye level near an unattended ATM in Minato Ward, according to the Metropolitan Police Department and bank officials.
The bank then removed all boxes in 1,600 unattended ATMs nationwide.
But in October, more boxes with hidden cameras were found in several ATMs in the Tokyo area, they said.
Police and the bank suspect the cameras, which can transmit images, were to photograph customers' as they entered their PINs.
The bank has checked unattended ATMs nationwide and is contacting people who might have had their PINs photographed to advise them to change their numbers.
UFJ said it filed a complaint about the incident with the Metropolitan Police Department on Monday.