Hackers attacked the internet and television services that cover the Pyeongchang Winter Olympic games in South Korea, although the operations were not disrupted.
The attack occured during Friday's opening ceremony of the games, according to the organizers.
"We are not going to comment on the issue. It is one we are dealing with. We are making sure our systems are secure and they are secure," said International Olympic Committee (IOC) spokesman Mark Adams. He refused to recognize the identity of the attackers.
South Korea has been using the Pyeongchang Games to break the ice with North Korea, while Russia has been banned from the Games for doping.