TikTok has soared in popularity worldwide, but its ownership by Chinese technology giant ByteDance -- and alleged subservience to Beijing's ruling Communist Party -- has fuelled national security concerns in Western capitals.

On Wednesday, the US House of Representatives overwhelmingly approved a bill that would force TikTok to divest from its parent company or face a nationwide ban.

The bill is yet to pass the Senate, where it is expected to face a tougher test in order to become law.

The White House has said President Joe Biden would sign the bill -- known officially as the Protecting Americans from Foreign Adversary Controlled Applications Act -- if it reaches his desk.

Mnuchin on Thursday said he is putting together a team of investors to buy TikTok from its Chinese owners, once the bill passes.

"I think the legislation should pass and I think (TikTok) should be sold," Mnuchin, an investment banker who led the Treasury Department throughout Trump's term in office, told CNBC.

Mnuchin said TikTok was "a great business and I'm going to put together a group to buy" the embattled app.

"This should be owned by US businesses. There's no way that the Chinese would ever let a US company own something like this in China," he said.

China has blocked Western online platforms such as Facebook and X (formerly Twitter) for years on its heavily-censored internet.

TikTok didn't immediately respond to requests for comment.

Mnuchin gave no further details on his plan, nor the investors he was trying to assemble.

ByteDance, which is privately run, has major US shareholders including investment giants Kohlberg Kravis Roberts and General Atlantic as well as Silicon Valley stalwart Sequoia Capital.

Hedge funder Jeff Yass is also a major investor in ByteDance and is reported by US media as being among those lobbying against the bill.

In a turnaround from his earlier stance, Trump this week said he is against the bill, but denied accusations that he changed his tune because Yass is donating to his campaign.

Any divestment of TikTok, either as a whole or just its US operations, would be a huge challenge, notably in the courts, and a transaction that only the world's richest companies could afford.

Any attempt by a US tech giant to buy TikTok, with its 170 million US users, would almost certainly face intense antitrust scrutiny.