(CNN NEWSOURCE) — Nintendo has announced that 300,000 of its customer accounts have been hacked.

The video game and electronics company first discovered the breach in April, revealing hackers had been using Nintendo network IDs without permission.

Originally, Nintendo said only 160,000 accounts were involved, but its continued investigation resulted in that number being revised.

Nintendo said only a small number of the hacked accounts were used to make fraudulent purchases. It said refunds to those customers are nearly complete.

The company is e-mailing affected users, urging them to change their passwords.