The push on Capitol Hill to rein in China-owned social media network TikTok has set its sights on tech giants Apple and Google.
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Sen. Michael Bennet, D-CO, sent a letter to Apple CEO Tim Cook and Google CEO Sundar Pichai on Thursday calling on their companies to remove TikTok from their respective app stores, citing concerns about how TikTok handles the data of American users.
"Like most social media networks, TikTok collects vast and sophisticated data from its users," Bennet said. "Unlike most social media networks, TikTok poses a unique concern."
"TikTok's vast influence and aggressive data collection pose a specific threat to U.S. national security because of its parent company's obligations under Chinese law," Bennet added.
TikTok, which has more than 100 million monthly active users in the U.S., has faced growing scrutiny from state and federal officials over fears that American data could fall into the possession of the Chinese government.
In December, Congress banned TikTok from all devices owned by the federal government. TikTok CEO Shou Zi Chew is scheduled to appear before the House Energy and Commerce Committee in March on the company's data security practices, the committee said on Monday.
More than half of U.S. states have taken steps toward a partial or full ban of TikTok on government devices.
The Biden administration and TikTok wrote up a preliminary agreement to address national security concerns posed by the app but obstacles remain in the negotiations, The New York Times reported in September.
TikTok said it stores the data of U.S. users outside of China, and has never removed U.S. posts from the platform at the request of the Chinese government.
Google and Apple did not immediately respond to a request for comment.
"Unfortunately, Senator Bennet's letter relies almost exclusively on misleading reporting about TikTok, the data we collect, and our data security controls," TikTok told ABC News in a statement.
"It also ignores the considerable investment we have made through Project Texas—a plan negotiated with our country's top national security experts—to provide additional assurances to our community about their data security and the integrity of the TikTok platform," the company added.
"We are disappointed that many state agencies, offices, and universities will no longer be able to use TikTok to build communities and connect with constituents," the company added.
Recent news stories have called into question the security of user data.
Buzzfeed reported in June that TikTok engineers based in China gained access to intimate information on U.S. users, such as phone numbers. Forbes reported in October that ByteDance, TikTok's parent company, intended to use the app to access information on some users.
The Trump administration tried to ban TikTok in 2020, eventually calling on ByteDance to sell the app to a U.S. company. However, the sale never took place.
In his letter on Thursday, Bennet said TikTok poses "an unacceptable threat to the national security of the United States."
Bennet addressed Cook and Pichai directly: "Given these grave and growing concerns, I ask that you remove TikTok from your respective app stores immediately."