A Japanese online dating service provider says hackers may have stolen personal information of about 1.7 million members.
Tokyo-based Net Marketing says a suspicious access was made to the server that stores the information on the members of the Omiai service on April 28.
The company launched a probe and found that the service received multiple instances of unauthorized access between April 20 and 26.
It also found that digital images of driver's licenses, health insurance cards and passports of up to 1.71 million members may have been leaked.
The data had been submitted to verify the members' ages.
Net Marketing says it has no confirmation that the personal information has been misused, but it is consulting with police to respond to the case.