In an email sent to employees Friday morning and obtained by CNN, Amazon (AMZN) said that due to "security risks, the TikTok app is no longer permitted on mobile devices that access Amazon email."
Accessing TikTok from company laptops is still permitted, the email said, but mobile devices will be cut off from Amazon email unless the app is removed.
Amazon didn't immediately respond to a request for comment. In a statement, a TikTok spokesperson said Amazon "did not communicate to us before sending their email, and we still do not understand their concerns."
"We welcome a dialogue so we can address any issues they may have and enable their team to continue participating in our community," the spokesperson added. "We're proud that tens of millions of Americans turn to TikTok for entertainment, inspiration, and connection, including many of the Amazon employees and contractors who have been on the frontlines of this pandemic."
The announcement marks the biggest company yet to warn its employees of TikTok as a possible security risk, following claims by US politicians that the app could undermine national security given its ties to China. Cybersecurity experts have been more cautious about that assessment.
TikTok is owned by the world's most valuable startup, a Chinese company named ByteDance. But TikTok does not operate in China and functions as an independent subsidiary. TikTok has been taking pains to draw that distinction, recently naming an American CEO and pointing out that its servers are based in the US and not subject to Chinese laws.
Amazon isn't the only organization to ban TikTok. The US military has prevented soldiers from installing the app, while some policymakers, such as Sen. Josh Hawley, have proposed banning TikTok from all US government devices.
On Friday, the Democratic National Committee warned Democratic campaigns, committees and state parties to take additional security precautions when using TikTok. In an email obtained by CNN, the DNC's security team wrote: "We continue to advise campaign staff to refrain from using TikTok on personal devices. If you are using TikTok for campaign work, we recommend using a separate phone and account."
The DNC suggested to campaigns in a memo in December not to use TikTok, citing concerns about the app's "Chinese ties and potentially sending data back to the Chinese government."
Amazon's decision is notable given it has previously advertised on the platform. In April, for example, Amazon ran a sponsored post on TikTok for a Jonas Brothers concert that streamed on Amazon Prime Video, according to Rich Greenfield, a media industry analyst at LightShed Partners.
TikTok has been downloaded 165 million times in the US and has become a key part of internet and popular culture, serving as a platform for viral memes, political satire and activism.
Donie O'Sullivan contributed to this repor
