After a proposed US ban of TikTok, Chinese messaging app WeChat and others are also falling into the crosshairs, as the Trump administration expands efforts to clamp down on Chinese-made technology in the US.

Secretary of State Mike Pompeo said on Wednesday Chinese apps "are significant threats to personal data of American citizens" and named TikTok and WeChat. "We want to see untrusted Chinese apps removed from US app stores," he told reporters at a press briefing.

Purging Chinese apps from US app stores is part of a program Pompeo announced Wednesday titled "Clean Network". The "comprehensive approach to guarding" American privacy and information would focus on "cleaning" five areas - carrier, store, apps, cloud and cable.

Pompeo said the State Department would work with the Commerce Department as well as the Defense Department to limit the ability of Chinese cloud service providers to collect, store and process data in the US.

In addition to restricting apps and cloud services, the Trump administration also seeks to prevent US apps from being preinstalled or made available for download on mobile devices manufactured by Huawei and "other untrusted vendors", and prevent Chinese carriers from connecting to US telecoms networks.

"So did the US just announce it is building a great firewall?" said Adam Segal, director of the Program on Digital and Cyberspace Policy at the Council on Foreign Relations, in response to the "Clean Network".

There's "no indication on how this is supposed to happen, or if anyone else was warned/consulted to see if they would go along," he said in a Twitter post.

"He (Pompeo) describes Chinese companies as "UNCLEAN." Can you say RACIST and PARANOID?" said Susan Aaronson, research professor and director of the Digital Trade and Data Governance Hub at George Washington University. "And bad policy," she added.

Pompeo's announcement comes after President Donald Trump threatened to ban TikTok last week. The hugely popular video-sharing app has come under fire from American lawmakers and the administration over alleged national security concerns.

Despite repeated denial of the allegations, TikTok faces a deadline of Sept 15 to either sell its US operations to Microsoft Corp or face an outright ban.

WeChat, owned by Chinese tech giant Tencent, is the largest communication app in China. Unlike TikTok, which is primarily used by young adults in the US, WeChat is primarily used by overseas Chinese and global businesses with a footprint in the Chinese market.

A potential WeChat ban has been loudly discussed on social media after White House trade adviser Peter Navarro suggested a few weeks ago that people should "expect strong action" on WeChat and TikTok in the US, calling the two apps "the biggest forms of censorship on the Chinese mainland".

If WeChat was actually banned in the US, it would not only affect overseas Chinese who rely on the app to connect with their families and friends in China, but also businesses which have increasingly been using WeChat to reach Chinese customers, particularly millennials and Gen Zers.

This latest move by the Trump administration represents another escalation of the tensions between China and the US.

John Pilger, an Australian writer and filmmaker, encouraged people to speak up against "the fanatic Pompeo's lies about China, now leading us to war".

Fears of a "China threat" were nonsense, he said in an article. "What was threatened was America's unchallenged psychopathic view of itself as the richest, the most successful, the most 'indispensable' nation," he said.