IOC's website www.Iocl.Com was this evening hacked with its front page defaced with a message from TurkGuvenligi which claimed the site was "HACKED".
It said, "hacking is not a crime".
TurkGuvenligi, according to its twitter account, is a hacking group focused on network systems.
IOC quickly restored the website. "The site was down for a brief while. We have been able to resolve issues and it is up and running now," a company official said.