2018 Winter Olympics organizers established that the Games’ systems were hacked two days ago in a cyber attack that took their internet and television services offline, according to Reuters. The organizers have not revealed who is responsible for the attack, but they emphasized that the hack did not affect any critical part of the operation.

“There was a cyber-attack and the server was updated yesterday during the day and we have the cause of the problem,” Pyeongchang 2018 spokesperson Sung Baik-you told the Guardian. “They know what happened and this is a usual thing during the Olympic Games. We are not going to reveal the source.”

Rumors have been circulating that cyber attacks could be orchestrated by North Korea, which is located just 50 miles from the Game’s site in Pyeongchang, or by Russia, in retaliation for its team being banned from the 2018 competition due to its major doping scandal. 

“We are not going to comment on the issue. It is one we are dealing with,” International Olympic Committee (IOC) spokesman Mark Adams said. “We are making sure our systems are secure and they are secure.”

Russian officials have already been denying reports that they are responsible for any cyber attacks since before the opening ceremony Friday. “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. “Of course, no evidence will be presented to the world.”

The defense is most likely in response to reports that state-backed hackers have been trying to infiltrate the Olympics’ systems for months. As pointed out by Gizmodo, the New York Times uncovered evidence of hackers targeting the games, many of which appear to be linked to Kremlin retaliation schemes.

As of now, the recent attack does not appear to have any serious effect on this year’s competition.