The agency says more than 450 million cyberattacks were aimed at the 2020 Tokyo Olympics and Paralympics.
The FBI on Monday warned US athletes heading to the Winter Olympics next month in Beijing to bring a burner phone, citing a heightened risk of cyberattacks because of the event's size.
"These activities include distributed denial-of-service attacks, ransomware, malware, social engineering, data theft or leaks, phishing campaigns, disinformation campaigns, and insider threats," the agency said in a release.
Last month, Team USA reportedly told this year's Olympic athletes to leave their personal phones behind. It encouraged Americans competing in the games to instead take temporary phones to prevent potential surveillance, The Wall Street Journal reported on Jan. 14.
Team USA and the International Olympic Committee didn't immediately respond to a request for comment.
The warning came after the Biden administration in December confirmed that no US officials will attend the 2022 Winter Olympics in Beijing, staging a diplomatic boycott against China's human rights violations.
"The Biden administration will not send any diplomatic or official representation to the Beijing 2022 Winter Olympics and Paralympic Games, given the PRC's ongoing genocide and crimes against humanity in Xinjiang, and other human rights abuses," press secretary Jen Psaki said during a Dec. 6 press briefing. "The athletes on Team USA have our full support."
The Winter Olympic Games are scheduled to kick off this Friday and include seven new sports, such as monobob -- a women-only bobsled competition.
Read more: How to watch the Beijing Winter Olympics: Everything to know