President Donald Trump on Friday ordered the Chinese company ByteDance to divest its interest in video-sharing app TikTok's operations in the United States within 90 days.
"There is credible evidence that leads me to believe that ByteDance ... might take action that threatens to impair the national security of the United States," Trump said in the order.
The move adds to pressure for ByteDance to divest TikTok, and legally buttresses the Trump administration's crackdown on the Chinese-owned social media app.
ByteDance did not immediately respond to a request to comment.
TikTok has come under fire from US lawmakers over national security concerns surrounding data collection. Last week, Trump issued an executive order that would ban US transactions with ByteDance and with Tencent Holdings Ltd's WeChat in 45 days, escalating a confrontation with Beijing over the future of the global tech industry.
Trump has said he would support an effort by Microsoft Corp to buy TikTok's American operations if the US government got a "substantial portion" of the proceeds, but has also said there are other interested potential buyers. Trump nevertheless said he will ban the popular app on September 15, though some Republicans have raised concerns about potential political fallout.
The Trump administration has stepped up its efforts to purge what it deems "untrusted" Chinese apps from US digital networks.
Asked on Friday if he was concerns that the sweeping bans on transactions with WeChat could prevent Apple Inc from selling iPhones in China, Trump did not express worry.
"I do what's good in terms of the security of our country," he told reporters.
A group of major US companies including Apple this week raised concerns about the potential negative implications on US firms from the TikTok and WeChat orders.