China on Saturday launched a mechanism that would allow it to sanction foreign companies, upping the ante in a tech war with the United States a day after Washington moved to curb popular Chinese apps TikTok and WeChat.

China's long-expected "unreliable entities list" is seen as a weapon for Beijing to retaliate against the United States, which has used its own "entity list" to shut Chinese telecom giant Huawei out of the US market, while also moving against TikTok and WeChat.

Its implementation comes just a day after the US Commerce Department stepped up the pressure by ordering a ban on downloads of video app TikTok and effectively blocking use of WeChat, the Chinese super-app.

An announcement by China's Ministry of Commerce did not mention any specific foreign entities that could be targeted.

But it said the new system would consider sanctions on entities whose activities "harm China's national sovereignty, security, and development interests" or violate "internationally accepted economic and trade rules".

President Donald Trump has claimed Chinese tech operations such as TikTok may be used for spying
President Donald Trump has claimed Chinese tech operations such as TikTok may be used for spying GETTY IMAGES NORTH AMERICA / Mario TAMA

That language closely tracks wording that Beijing has used to repeatedly denounce US actions against Chinese companies.

Punitive measures may include fines against the foreign entity, banning it from conducting trade and investment in China, and restrictions on the entry of personnel or equipment into the country.

It covers "foreign enterprises, other organisations and individuals", the ministry said.

WeChat, the Chinese super-app used for messaging, shopping, payments and other services, is set to be banned in the United States, which claims it poses a national security threat
WeChat, the Chinese super-app used for messaging, shopping, payments and other services, is set to be banned in the United States, which claims it poses a national security threat AFP / Martin BUREAU

Under Friday's US order against the Chinese apps, Tencent-owned WeChat would lose functionality in the United States from Sunday. TikTok users will be banned from installing updates but could keep accessing the service through November 12.

That timeframe potentially allows for a tie-up between TikTok, owned by China's ByteDance, and a US company to safeguard data for the wildly popular app to allay Washington's security concerns.

With President Donald Trump facing a tough re-election campaign, US officials have described the measures as essential to safeguard national security from potential Chinese espionage through the platforms.

But in a response to the US steps, China's Commerce Ministry on Saturday condemned what it called US "bullying", saying it violated international trade norms and that there was no evidence of any security threat, shortly before announcing the new sanctions regime.

Bytedance late Friday asked a US court to block the ban on downloading the TikTok app, asserting that it would respect the security and privacy of American users.

Silicon Valley tech firm Oracle is seeing a deal to become the technology partner of TikTok to avert a ban of the popular video app in the United States
Silicon Valley tech firm Oracle is seeing a deal to become the technology partner of TikTok to avert a ban of the popular video app in the United States GETTY IMAGES NORTH AMERICA / JUSTIN SULLIVAN

The administration's decision was made "for political reasons rather than because of any 'unusual and extraordinary threat' to the United States," the parent company said in the court filing.

It also maintained that the ban violates the right to free speech as well as due process, both enshrined in the US Constitution.

Critics added that while the security risks were unclear, the sweeping ban raises concerns about the US government's ability to regulate free expression.

"It's a mistake to think of this as (only) a sanction on TikTok and WeChat. It's a serious restriction on the First Amendment rights of US citizens and residents," said Jameel Jaffer, director of the Knight First Amendment Institute at Columbia University.

Some analysts say Trump's moves are motivated more by business competition than security concerns.

The moves would effectively disable US use of WeChat -- a so-called super-app used for messaging, shopping, payments and other services -- and TikTok from the online marketplaces operated by Apple and Google.

After Sunday, services on WeChat will be "degraded", said a senior US Commerce Department official, who added that existing users may retain some capability.

WeChat is widely used among Chinese expats to keep in touch with people back home. A court challenge to the ban by US-based WeChat users is pending.

Existing TikTok users will be able to continue using the app until November 12 -- when it would also face a full ban on its US operations if no deal is reached, according to officials.

TikTok's brand of brief, quirky phone videos has become hugely popular, especially among young people, with 100 million users in the US alone.

One potential deal would allow Silicon Valley giant Oracle to become the tech partner for TikTok, but some US lawmakers have objected to allowing ByteDance to keep a stake.

Trump said Friday a deal could happen quickly.

"For ByteDance, their back is against the wall to accept the terms of the deals outlined over the past few days," Daniel Ives at Wedbush Securities said in a research note.

"We still believe a deal can be reached and this shutdown averted although it's a critical 48 hours ahead for deal negotiations between all parties involved."