President Donald Trump said Monday the U.S. government should get a "substantial portion" of the sales price of the U.S. operations of popular short-video app TikTok and warned he will ban the service in the United States on Sept. 15 without a sale.

The turnaround came after Trump on Friday said he was planning to ban the Chinese-owned video app's U.S. operations as soon as Saturday after dismissing a possible sale to Microsoft.

Reuters reported last week that some investors are valuing TikTok at about $50 billion, citing people familiar with the matter.

"I did say that if you buy it, whatever the price is that goes to whoever owns it, because I guess it’s China essentially … I said a very substantial portion of that price is going to have to come into the Treasury of the United States because we’re making it possible for this deal to happen," Trump said.

Trump later defended his push for a cut, adding "nobody else would be thinking about but me, but that's the way I think."

Nicholas Klein, a lawyer at DLA Piper, said generally "the government doesn't have the authority to take a cut of a private deal through" the Committee on Foreign Investment in the United States (CFIUS), which is the interagency committee that reviews some foreign investments in the United States. It was not clear how the U.S. government would receive part of the purchase price.