The United States Olympic and Paralympic Committee is telling athletes to ditch their personal phones for burners ahead of next month’s Winter Olympics in China, according to a report from the Wall Street Journal, Report informs via The Verge.

The advisory was reportedly sent out twice last year to warn athletes about the possibility of digital surveillance while in China. “Every device, communication, transaction and online activity may be monitored,” the bulletin states. “Your device(s) may also be compromised with malicious software, which could negatively impact future use.” As noted by the WSJ, Great Britain, Canada, and the Netherlands have also cautioned athletes against bringing their personal electronics into the country.

The Committee’s fears aren’t unfounded. In 2019, China was caught secretly installing spyware on tourists’ phones who entered from the Xinjiang region. This heavily-surveilled area is populated by the Uyghurs, a predominantly Muslim ethnic minority that China has subjected to imprisonment and torture. In addition, research group Citizen Lab found that China’s My2022 Olympic app, which all attendees are required to install, is full of security holes that could lead to privacy breaches, surveillance, and hacking.

Back when Beijing held the 2008 Summer Olympics, the US Department of Homeland Security issued a similar advisory for any travelers headed to China, warning that bringing any devices potentially exposes them to “unauthorized access and theft of data by criminal or foreign government elements.” Things are a bit different this time around, however, as China has banned all foreign spectators due to concerns over COVID-19. Athletes will likely be relying on their mobile devices to stay in touch with friends and family, which could be more complicated on a burner phone that comes with limits on mobile data, texting, and calling.

But even if the Olympic athletes want to use their burner phones to browse the internet, they still might not get unlimited access. During the 2008 Olympics, China promised to offer spectators, journalists, and athletes unrestricted access to the web, since The Great Firewall of China currently blocks a number of popular websites in the country, like Google, YouTube, Twitter, Facebook, Netflix, and more. China didn’t seem to follow through on its promise, however. Journalists reported that they still weren’t able to access certain websites, including BBC China, a number of Hong Kong newspapers, as well as the site for human rights organization Amnesty International.