US PRESIDENT Donald Trump signed executive orders banning TikTok and the social-media app WeChat today, escalating the crackdown on Chinese-developed technology.

Song-and-dance app TikTok said it was “shocked” by the ban and would be taking legal action against it.

It would pursue all avenues to ensure that “the rule of law is not discarded,” it said, noting it had engaged with the US government “in good faith” for over a year over Washington’s accusations that it poses a national-security threat.

The Trump administration claims that the Chinese government has access to user information gathered by TikTok, but has not provided evidence and the firm denies it.

“What we encountered is that the administration paid no attention to facts, dictated terms of an agreement without going through standard legal processes and tried to insert itself into negotiations between private businesses,” TikTok said.

TikTok’s parent company, ByteDance, has been seeking to sell its US operation to Microsoft, but Mr Trump says that if the sale proceeds a “substantial portion” of the sale price should go to the US Treasury, because the deal would send money into China so the US should receive money in return. The legal basis for such an arrangement is unclear.

WeChat’s owner, TenCent, said it was assessing the implications of the ban. The largest standalone mobile app in the world, with over a billion monthly users, WeChat is a multi-purpose “super-app” used for messaging and payments mostly used inside China, but the ban may affect the activities of US corporations active in China – including McDonald’s, Starbucks, Disney and Apple  – since their Chinese operations rely on WeChat for “payments, promotion and sales,” in the words of Bloomberg’s Tom Mackenzie.