The Games’ systems, including the internet and television services, were affected by the hack two days ago but organisers said it had not compromised any critical part of their operations.

International Olympic Committee spokesman Mark Adams refused to talk about the issue saying it was "being dealt with. We are making sure our systems are secure, and they are secure.”

Asked if organisers knew who was behind the attack, Adams said: “I certainly don’t know. But best international practice says that you don’t talk about an attack.”

Obviously, North Korea would be a logical candidate. The Winter Games are being staged only 80km (50 miles) from the border with North Korea, which is technically still at war with the South since their 1950-1953 war ended in a truce rather than a peace treaty.

But South Korea has been using the Pyeongchang Games to break the ice with the reclusive North and the two countries marched as a single team during the opening, which makes it unlikely to be the north.

A better candidate is Russia, which has been banned from the Games for doping. There is a small chance that they might have a little grudge about this. But Russia said it did not do it. It would never hack anyone, never, ever and anyone who says they do is a "liar, liar pants on fire".

“We know that Western media are planning pseudo-investigations on the theme of ‘Russian fingerprints’ in hacking attacks on information resources related to the hosting of the Winter Olympic Games in the Republic of Korea”, Russia’s foreign ministry said.

Cybersecurity researchers said in January they had found early indications that Russia-based hackers may be planning attacks against anti-doping and Olympic organisations in retaliation for Russia’s exclusion from the Pyeongchang Games.