With the end of his presidency looming, Donald Trump on Tuesday launched a crusade against Chinese apps, branding them a threat to US national security.

Trump ordered a ban on transactions involving Alipay, WeChat Pay and other apps linked to Chinese companies, saying they could route user information to the government in Beijing.

The executive order is to take effect in 45 days, just weeks after Trump is replaced in the White House by President-elect Joe Biden on January 20.

A senior administration official said the order and its implementation have not been discussed with the "potential incoming Biden administration."

The move by Trump comes after previous executive orders aimed at banning TikTok, which is owned by China-based ByteDance, were derailed by court rulings indicating Trump overstepped his legal authority.

The apps targeted by the new ban were chosen because of the extremely high number of downloads, which meant tens of millions of users could be at risk of having their data harvested, according to the administration official.

"We are trying to articulate to the world and take steps to stop the encroachment of China's big data strategy -- photos, text messages, phone calls to parents -- from being fed into this mass tool for global oppression," the official said.

Trump's order calls for the secretary of commerce to review and assess what further apps should be included in the ban.

It specifically named Alipay, CamScanner, QQ Wallet, SHAREit, Tencent QQ, VMate, WeChat Pay and WPS Office.

Alipay and Tencent did not respond to queries.

- Details vague -
The executive order leaves it to the secretary of commerce to recommend which kinds or transactions with apps to prevent and how.

"Not earlier than 45 days after the date of this order, the Secretary shall identify the transactions and persons that develop or control the Chinese connected software application," the order stated.

The Trump administration last week appealed a federal court ruling which allows TikTok to keep operating in the United States despite a move to block the popular social media application on national security grounds.

The Justice Department filed the appeal seeking to enforce a ban on TikTok ordered by Trump, who has argued that the app's Chinese parent company may use TikTok for espionage and to spread disinformation.

The ban had been rejected by US District Judge Carl Nichols and in a parallel case filed in Pennsylvania.

Nichols said TikTok's lawyers had demonstrated that the Commerce Department likely overstepped its authority by seeking to ban the popular social media app and "acted in an arbitrary and capricious manner by failing to consider obvious alternatives."

TikTok has repeatedly defended itself against allegations of data transfers to the Chinese government, saying it stores user information on servers in the United States and Singapore.

TikTok has a further fight on its hands over an August 14 executive order from Trump to force ByteDance to sell its US operations to an American buyer.

Washington is in a tense trade battle with Beijing, and Trump's administration has stepped up warnings about China's growing economic and military power.