TikTok is threatening legal action against the US after Donald Trump ordered firms to stop doing business with the Chinese app within 45 days.
The company said it was “shocked” by an executive order from the US President outlining the ban.
TikTok said it would “pursue all remedies available” to “ensure the rule of law is not discarded”.
Mr Trump issued a similar order against China’s WeChat in a major escalation in Washington’s stand-off with Beijing.
WeChat’s owner, Tencent, said: “We are reviewing the executive order to get a full understanding.”
As well as WeChat, Tencent is also a leading gaming company and its investments include a 40% stake in Epic Games – the company behind the hugely popular Fortnite video game.
The president has already threatened to ban TikTok in the US, citing national security concerns, and the company is now in talks to sell its American business to Microsoft. They have until 15 September to reach a deal – a deadline set by Mr Trump.
The Trump administration claims that the Chinese government has access to user information gathered by TikTok, which the company has denied.
TikTok, which is owned by China’s ByteDance, said it had attempted to engage with the US government for nearly a year “in good faith”.
However, it said: “What we encountered instead was 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.”
The executive orders against the short-video sharing platform and the messaging service WeChat are the latest measure in an increasingly broad Trump administration campaign against China.