"The president reiterated our concerns about the ownership of TikTok," National Security Council spokesman John Kirby told reporters after a wide-ranging telephone call between the two leaders.

"He made it clear to President Xi that this was not about a ban of the application, but rather our interest in divestiture, so that the national security interest and the data security of the American people can be protected," Kirby said.

Western officials have voiced alarm over the popularity of TikTok with young people, alleging that it is subservient to Beijing and a conduit to spread propaganda, claims denied by the company and Beijing.

The US House of Representatives last month overwhelmingly approved a bill that would force TikTok to divest from Chinese parent company ByteDance or face a nationwide ban.

Biden has supported the effort even though his campaign has turned to TikTok to reach young voters.

The bill faces less certain prospects in the Senate, with some members saying that the United States is overstepping its authority on civil liberties and business ownership.

Biden's election rival Donald Trump has also voiced unease, even though he is usually eager to denounce China.