The FBI has told Olympic athletes to leave their personal cell phones at home and instead take burner phones to the Beijing Winter Olympics this month, citing the potential for “malicious cyber activities.”

“The FBI urges all athletes to keep their personal cell phones at home and use a temporary phone while at the games. The National Olympic Committees in some Western countries are also advising their athletes to leave personal devices at home or use temporary phones due to cybersecurity concerns at the Games,” the agency said in a notice.

While not aware of “any specific cyber threat against the Olympics” the FBI added that it’s important that those at the games be “vigilant and maintain best practices in their network and digital environments.”

The warning comes amid rising concerns by US national security officials about Chinese espionage and intellectual property theft.

Intelligence officials have also publicly warned that China has created an advanced techno-surveillance state within its borders, using cameras, facial recognition and other technology.

The US believes that US state and local officials, as well as members of business and academia, who travel to China face the risk of having their personal devices hacked. 

Due to this threat, the FBI routinely provides so-called defensive briefings to Americans it considers to be at risk of becoming victims of Chinese espionage efforts.

The FBI currently has open over 2,000 counterintelligence investigations into alleged efforts by Beijing to steal American information of technology, according to FBI Director Chris Wray.

“When we tally up what we see in our investigations, there is just no country that presents a broader threat to our ideas, our innovation, and our economic security than China,” Wray said during public remarks at the Ronald Reagan Presidential Library.

Due to the US’ stands off with China,  US athletes are allowed to compete in the Beijing Olympics but the Biden administration will not be sending government officials to the games. 

The same policy applies for the Paralympic Games, which are also taking place in Beijing. The White House is looking to send a “clear message” that the human rights abuses in China mean there cannot be “business as usual,” White House press secretary Jen Psaki said.