U.S. intelligence officials say that Russian hackers infiltrated South Korean routers, releasing malware just ahead of the 2018 Olympic Games in Pyeongchang, and then tried to sow discord among nations by disguising the attack as having come from North Korea.

The Washington Post reports that U.S. intelligence believes Russian hackers associated with the notorious GRU collective that boasts ties to the Russian government and Russian military, gained access to South Korean computers back in December. The Russians, the experts say, appear to have used that access to undertake a "false flag" operation aimed at breaking down relations between North and South Korea.

Although WaPo says intelligence experts haven't given many specifics about the Russian operation, it's likely the attack is connected to widespread internet outages, communications disruptions, and technical difficulties that South Korean Olympic officials experienced during the Opening Ceremonies. At one point, even the official Olympic website was unavailable, during what appeared to be a denial of service attack.

According to an intelligence report just released, U.S. officials believed that "the Russian military agency GRU had access to as many as 300 Olympic-related computers," and that Russian "cyber-operators also hacked routers in South Korea last month and deployed new malware on the day the Olympics began."

During the attack, the report says, hackers used North Korean IP addresses to disguise their true location and to lure officials into believing the attack came from Kim Jong Un.

The Russians are not new to Olympic skullduggery. Back in 1984, at the Summer Games held in Los Angeles, they tried to embarrass the U.S. by dropping fake Ku Klux Klan fliers near the African quarters in the Olympic Village in retaliation for a U.S.-led boycott of the 1980 Moscow Games. In 2016, the Russians hacked an athlete database and released sensitive information on some U.S. summer Olympians as a way of hitting back against Olympic officials who banned Russian track and field athletes for doping.

This time around, the Russian motivation is obvious: Russians were banned from competing under their national flag and Russian officials were not allowed to participate in the Winter Games after several Russian athletes tested positive for banned substances.