Amazon has told employees to delete the video app TikTok from phones on which they use company email, claiming security risks from the China-owned service, according to reports.
The notice said employees must delete the app by Friday to keep access to Amazon email. Workers would still be allowed to use TikTok from an Amazon laptop browser.
Amazon is the second-largest US private employer after Walmart, with more than 840,000 employees worldwide.
Amazon did not immediately reply to requests for comment.
In an emailed statement, TikTok said that Amazon did not notify it before sending the email.
“We still do not understand their concerns,” it continued, adding that the company would welcome a dialogue to address Amazon’s issues.
Chinese internet giant ByteDance owns TikTok, which is designed for users outside of China, as well as a Chinese version called Douyin.
The app is popular with young people, including millions of American users, but is the subject of national security concerns.
TikTok has been trying to appease critics in the US and distance itself from its Chinese roots, but finds itself caught in an increasingly sticky geopolitical web.
TikTok recently named a new CEO, top Disney executive Kevin Mayer, which experts said could help it navigate US regulators.
And it is stopping operations in Hong Kong because of a new Chinese national security law that led Facebook, Google and Twitter to also stop providing user data to Hong Kong authorities.
But a top Trump administration official said this week that the government remains concerned about the national-security threat to the app’s millions of US users.
When Fox News TV host Laura Ingraham suggested that the US bans Chinese social media apps, “especially TikTok”, Secretary of State Mike Pompeo said that “ee’re certainly looking at it”.
Mr Pompeo said the Trump administration has “worked on this very issue for a long time”, including its stance against Chinese telecom firms Huawei and ZTE.
The government has tried to convince allies to root Huawei out of telecom networks, saying the company is a national-security threat, with mixed success.
Huawei has denied that it enables spying for the Chinese government.
“With respect to Chinese apps on people’s cell phones, I can assure you the United States will get this one right too,” Mr Pompeo said, and added that if users downloaded the app their private information would be “in the hands of the Chinese Communist Party”.