Olympic officials in South Korea today said a cyber attack was responsible for an internet and wifi shutdown during the Pyeongchang Winter Games opening ceremony. South Korea's defence ministry and cybersecurity experts are included in the task force investigating Friday's attack, but the possible culprit is being kept under wraps. Internal systems crashed just before Friday's ceremony but didn't disrupt the high-tech gala, which was attended by VIPs including the sister of North Korean leader Kim Jong Un and US Vice-President Mike Pence.Cybersecurity experts had warned of potential attacks on the Winter Olympics, with both North Korea and Russia touted as possible sources. In January, a malware attack targeted organisations involved with the Olympics.