The United States has signalled that it may soon order Apple and Google to remove certain Chinese apps from their smartphone app stores, citing TikTok and WeChat as "significant threats".
US Secretary of State Mike Pompeo said on Wednesday that he would work to ban such apps from US app stores in order to protect Americans' personal data.
Mr Pompeo said apps seen as "untrusted" could face bans, without saying what would determine if an app was untrusted, but named TikTok and messaging app WeChat as examples. He said apps linked to the Chinese government "threaten our privacy, proliferate viruses, and spread propaganda and disinformation".
It came after an intervention by Donald Trump almost sunk negotiations between Microsoft and TikTok's parent company, ByteDance, to sell off the popular video app.
On Sunday, Mr Pompeo heralded broader action against Chinese tech firms, pledging to take action for national security reasons connected to China.
Mr Pompeo said on Wednesday: "With parent companies based in China, apps like Tiktok, WeChat and others are significant threats to personal data of American citizens, not to mention tools for Chinese Communist Party [CCP] content censorship....
"The United States calls on our allies and partners in government and industry around the world to join the growing tide to secure our data from the CCP’s surveillance state and other malign entities. Building a 'clean fortress' around our citizens’ data will ensure all of our nations’ security."
The new announcement is an expansion of the US government's "Clean Networks" programme, originally launched to freeze "authoritarian governments" out of Western 5G networks.
As well as action against untrusted apps, the US will attempt to prevent some Chinese smartphone makers from pre-installing "trusted" apps on their phones, in order to prevent Western app makers from "partnering with a human rights abuser".
Mr Pompeo also vowed to prevent sensitive personal and commercial data, including Covid-19 vaccine research, from being stored on cloud computing systems linked to Chinese companies such as Alibaba, Baidu and Tencent, and to prevent the exploitation of undersea internet cables.
It remains unclear how the US government will define "untrusted", and whether it applies to all Chinese apps or just some. It is likewise uncertain whether the government will work voluntarily with app store owners or force them to remove targeted apps.