Millions of Nintendo customers may have been affected by a serious breach of the games giantís Japanese website.

A massive breach of the Club Nintendo site revealed data including names, addresses, phone numbers and email addresses, according to The Japan Times. As many as 4 million Club Nintendo members in Japan may have had their data exposed.

A Nintendo spokesperson confirmed to TechWeekEurope no European or non-Japan customers had been hit.

Nintendo has told affected users to change their passwords. The firm said it saw around 15.46 million fraudulent login attempts from 9 June through to 4 July, and 23,926 of those were successful.

But it has not said when the attack took place or specified how many were affected. The spokesperson said Nintendo had nothing more to add outside of what was in the report.