The US Commerce Department said Friday it will ban Chinese-owned TikTok and WeChat from app stores in the country on Sunday.
It will also bar the apps from accessing essential internet services in the US, it added.
The move could effectively wreck the operation of both Chinese services for US users.
TikTok will not face the most drastic sanctions until after the November 3 election, but WeChat users could feel the effects as early as Sunday.
The order, which cited national security and data privacy concerns, follows weeks of dealmaking over the video-sharing service TikTok.
President Donald Trump has pressured the app's Chinese owner to sell TikTok's US operations to a domestic company to satisfy concerns over the company’s data collection and related issues.
California tech giant Oracle recently struck a deal with TikTok along those lines, although details remain foggy and the administration is still reviewing the agreement.
TikTok expressed “disappointment” over the move and said it would continue to challenge President Donald Trump's “unjust executive order.”
The Commerce Department is enacting an order announced by President Donald Trump in August, which TikTok brought legal action against.
WeChat owner Tencent said in an emailed statement that it will continue to discuss ways to address concerns with the government and look for long-term solutions.
The action is the Trump administration’s latest attempt to counter the influence of China, a rising economic superpower.
Since taking office in 2017, Trump has waged a trade war with China, blocked mergers involving Chinese companies and stifled the business of Chinese firms like Huawei, a maker of phones and telecom equipment.
China-backed hackers, meanwhile, have been blamed for data breaches of US federal databases and the credit agency Equifax.
The Chinese government strictly limits what US tech companies can do in China.
Like most social networks, TikTok collects user data and moderates users’ posts. It grabs users’ locations and messages and tracks what they watch to figure out how best to target adverts.
TikTok says it does not store US user data in China and that it would not give user data to the government, nor does it censor videos per dictates from China.