The 2018 Winter Olympics website was hit by a cyber-attack during the opening ceremony on 9 February, officials have confirmed.
As well as the website, TV and internet systems were also disrupted – although operations were restored about 12 hours later.
While officials have confirmed the cyber-attack, they have not revealed the source of the attack.
Speaking to the BBC, Mark Adams, a spokesperson for the International Olympic Committee said: “Maintaining secure operations is our purpose.”
Before the Games, there were concerns that Russia might try to target the event, after 43 Russian athletes were banned from competing.
But the Russian Foreign Ministry has denied that Russia was behind the cyber-attack.
A spokesperson said: “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.
"Of course, no evidence will be presented to the world.”