Japanese computer games publisher Sega has launched an investigation after hackers broke into its customer database, the BBC reported on Saturday, in the latest in a series of online corporate security breaches, according to Reuters. The technology company, known for its Sonic the Hedgehog games series, has written to customers to tell them that hackers got into the database for Sega Pass, its online gaming network, the BBC said. Computer hackers have also broken into the websites of Sony PlayStation, Nintendo and other multi-national bodies in a spate of attacks in recent weeks, raising concerns over the security of customers' details stored online. Sega Europe, based in London and part the Japanese group Sega Sammy Holdings Inc, was not immediately available for comment on the BBC report. British newspapers carried similar reports about the security breach. The BBC News website published extracts of an email it said Sega sent to customers explaining what had happened. "Over the last 24 hours we have identified that unauthorised entry was gained to our Sega Pass database," the extracts of the email said. "We immediately took the appropriate action to protect our consumers' data and isolate the location of the breach. We have launched an investigation into the extent of the breach of our public systems." Payment information, such as credit card numbers, remained safe as it was handled elsewhere, Sega added, according to the BBC report. The latest wave of hacking attacks has prompted calls for better training and monitoring to cope with the growing risk posed by online threats. Japan's Sony Corp said in April that hackers had stolen names, addresses and possibly credit card details from the 77 million user accounts of its video game online network, in one of the largest Internet security break-ins. The International Monetary Fund said last Saturday that hackers had launched a cyber-attack on its networks.