TOKYO—Nintendo Co. said Sunday that a server for its U.S. unit's website had been hacked but no company or customer information was compromised, marking the first time the Japanese gaming giant has been targeted in recent global hacking attacks.

The Nintendo breach is less severe than the hacker attacks on rival Sony Corp.'s PlayStation Network and its other online services since April that have led to a personal data breach involving more than 100 million user accounts.

The Nintendo incident involved no sensitive information and hasn't caused any damage to its operations or inconveniences for its customers, the company said.

Still, the breach raises a question over whether any online services can be fully protected from potential hacking attempts.

A hacker group called Lulzsec, which had earlier claimed that it had broken into some of Sony's websites and stolen customer information, posted data on the Internet it claims was Nintendo "server configuration file," or data for programming purposes.