Popular video-sharing platform TikTok is on the brink of being banned in the United States, as the Supreme Court upheld the law on Friday, citing national security concerns. The final decision on the app's fate likely depends on President-elect Donald Trump.

The court dismissed an appeal by TikTok's owner, the Chinese company ByteDance. The firm had asked the court to stay the law on grounds that it infringes on freedom of speech and is unconstitutional.

Once the law takes effect, users in the US will no longer be able to download or update TikTok, unless ByteDance sells the platform's US business.

Although the law will take effect on Sunday, there is a possibility its enforcement will be postponed.

White House Press Secretary Karine Jean-Pierre acknowledged in a statement on Friday that actions to implement the law must fall to the next administration.

The Washington Post reported that US President-elect Donald Trump is considering an executive order to suspend the ban.

TikTok is said to be used by more than 170 million people, or about half of the population of the United States. It is especially popular among young people.