Organizers of the Pyeongchang Winter Olympics on Sunday confirmed the games’ opening ceremony was hit by a cyberattack late Friday, but they declined to disclose the source of the attack. “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,” International Olympic Committee spokesman Mark Adams was quoted as saying by Reuters. As for the culprit behind the attack, Adams said, “Best international practice says that you don’t talk about an attack.” Sung Baik-you, a spokesman for the Pyeongchang organizing committee, told reporters the source of the attack had been determined but a decision had been made not to reveal it. Organizers have stressed that the attack affected only the internet and Wi-Fi systems during the opening ceremony. The location of the Winter Games—a mere 50 miles from the border with North Korea—prompted warnings from security experts that the event would be a prime target for hackers, particularly from North Korea. Russian hackers were also suspected by experts of preparing possible cyberattacks on Winter Olympics organizations.