US President Donald Trump has signed an executive order to ban transactions with TikTok’s parent company ByteDance.
The executive order says the US “must take aggressive action against the owners of TikTok to protect our national security”.
Under the order, beginning in 45 days, any US transaction with ByteDance will be prohibited.
TikTok denies accusations it is controlled by or shares data with the Chinese government.
On Thursday night, he issued a follow-up executive order taking similar action to ban WeChat, an app owned by China-based tech giant Tencent.
What did Trump say?
In both executive orders, he says he has found “additional steps must be taken to deal with the national emergency with respect to the information and communications technology and services supply chain”.
He adds: “The spread in the United States of mobile applications developed and owned by companies in the People’s Republic of China (China) continues to threaten the national security, foreign policy, and economy of the United States.”
He refers to both apps as a “threat”.
Mr Trump said TikTok’s data collection could allow China to track US government employees and gather personal information for blackmail, or to carry out corporate espionage.
He noted that reports indicate TikTok censors content deemed politically sensitive, such as protests in Hong Kong and Beijing’s treatment of the Uighurs, a Muslim minority.
The US president said the Department of Homeland Security, the Transportation Security Administration (which oversees US airport screening) and the US Armed Forces have already banned TikTok on government phones.
What is TikTok?
The fast-growing app – which has up to 80 million active monthly users in America – has exploded in popularity in recent years, mostly with people under 20.
They use the app to share 15-second videos that often involve lip-synching to songs, comedy routines and unusual editing tricks.
These videos are then made available to both followers and strangers. By default, all accounts are public, although users can restrict uploads to an approved list of contacts.
TikTok also allows private messages to be sent but this facility is limited to “friends”.
The app is reported to have around 800 million active monthly users, with its biggest markets having grown in the US and India.
Though as Mr Trump notes in his executive order, India has already blocked TikTok, as well as other Chinese apps.
Australia, which has already banned Huawei and telecom equipment-maker ZTE, is also considering banning TikTok.