US President Joe Biden’s re-election campaign has defended its new TikTok account as a vital way to boost its appeal with young voters – even as his administration continued to raise security concerns about whether the popular social media app might be sharing user data with China’s government.

The campaign’s first post featured the president being quizzed on Sunday’s Super Bowl and included a reference to the latest political conspiracy theory involving pop superstar Taylor Swift.

“The President’s TikTok debut last night – with more than five million views and counting – is proof positive of both our commitment and success in finding new, innovative ways to reach voters in an evolving, fragmented, and increasingly personalised media environment,” Mr Biden’s re-election deputy campaign manager Rob Flaherty said in a statement.

At the White House, however, national security spokesman John Kirby said “there are still national security concerns about the use of TikTok on government devices and there’s been no change to our policy not to allow that”.

Mr Kirby referred most questions about TikTok to the Biden campaign and ducked a more general query about whether it was wise to use the app at all.

He said the potential security issues “have to do with concerns about the preservation of data and potential misuse of that data and privacy information by foreign actors”.

Both the FBI and the Federal Communications Commission have warned that TikTok’s Chinese owner, ByteDance, could share user data – such as browsing history, location and biometric identifiers – with that country’s authoritarian government.

Biden signed legislation banning the use of TikTok by the federal government’s nearly 4 million employees on devices owned by its agencies in 2022, with limited exceptions for law enforcement, national security and security research purposes.

Separately, the secretive Committee on Foreign Investment in the US has been reviewing the app for years while trying unsuccessfully to force TikTok ownership to divest from its parent company.

The White House said on Monday the review is ongoing.

With 150 million US users, TikTok is best known for quick snippets of viral dance routines.

But senator Josh Hawley posted on X, formerly Twitter, that Mr Biden’s campaign is “bragging about using a Chinese spy app even though Biden signed a law banning it on all federal devices”.

The Biden campaign said it had been mulling over setting up a TikTok account for months and had ultimately done so at the urging of youth activists and organisations, who argued that the app was key to reaching young voters.

The campaign said it is using a separate mobile phone to engage on TikTok in order to isolate using the app from other workstreams and communications, including emails.

The campaign said it was taking additional steps but declined to name them, citing security concerns.

White House press secretary Karine Jean-Pierre said she isn’t in contact with the campaign and had no advance warning that its TikTok account was going live.