U.S. intelligence officials say Russian military spies hacked hundreds of computers at the 2018 Olympic Games opening ceremony in South Korea and attempted to disguise it as the work of North Korea.

Two anonymous U.S. officials told the Washington Post that members of the Russian military agency GRU used North Korean IP addresses to cover their tracks in a "false flag" operation that gave them access to 300 computers. Accessing South Korean routers, they reportedly sent out malware on the day of the opening ceremony, which led to internet and broadcast disruptions. Some attendees weren't able to attend the ceremony after several ticket printing computers were shut down.

Shortly after the Olympics began, a group linked to the GRU called "Fancy Bear" leaked a set of stolen emails, which was likely linked to the opening ceremony hack. It hasn't been confirmed exactly what the effects of the hack were, but former National Security Agency cyber-operator Jake Williams told the Washington Post, "Anyone who controls a router would be able to redirect traffic for one or more selected targets or cause total disruption in the network by stopping the routing entirely."

Many believe that the hack was carried out in retaliation to the International Olympic Committee banning Russia from competing in Pyeongchang as punishment for a government-run doping scheme in the 2014 Sochi Winter Olympics as well as the 2016 Rio de Janeiro Olympics.

Russia's Olympic federation officials weren't allowed to attend this year's Olympics, but nearly 200 athletes from Russia were allowed to participate as long as they competed as "Olympic Athletes from Russia" and didn't wear Russian colors or display the country's flag.

There was a chance that the Russian athletes would be reinstated and allowed to march behind their flag during Sunday's closing ceremonies, but the IOC voted unanimously on Sunday to uphold the suspension. Between these hacking allegations and multiple Russian athletes failing drug tests, the country hasn't exactly been on its best behavior during this year's Olympics. IOC official Nicole Hoevertsz did say that Russia could be reinstated within the next week if their final doping test results come back clean, however.

This is the latest in a long line of Russian interference in major global events, including the 2016 U.S. presidential election and the 2016 Summer Olympics in Rio.