Jake Sullivan, President Biden's national security adviser, met with Marco Rubio, a Florida Republican, to talk about China and industrial policy. Mr. Rubio was worried about Beijing's influence over TikTok.

TikTok was under scrutiny over whether it could compromise US national security by sharing information with China. The issue was taken over by the Biden Administration. Mr. Sullivan shared his concerns with us.

They had a discussion with a government official about TikTok. The Democratic chairman of the Intelligence Committee, Mark Warner of Virginia, said he had been talking to the administration about the app. Regulators and other government officials are considering what to do about it.

Tensions over TikTok have arisen in Washington. While the app appeared to fade as a political flashpoint after Mr. Trump left office, lawmakers and government officials have privately grown frustrated over the lack of progress in policing Chinese apps that could leak data to Beijing.

Recent revelations about TikTok's data practices and ties to its Chinese parent have boiled over into the public eye. The Federal Trade Commission and the Federal Communications Commission have both called for investigations into the app.

A group of Republican senators demanded answers from TikTok about who could see their data. According to an email obtained by The New York Times, officials in the House of Representatives told staff members not to use or download the service due to security concerns.

The Biden administration has made progress on TikTok but it has not been a priority over there.

The bipartisan scrutiny of TikTok is at its most intense since Mr. Trump tried to force the app's sale to an American buyer The scores of young people who posted last month about dressing in suits to see the latest "Minions" movie are examples of how TikTok has become a prime engine for cultural phenomena. According to a report last week, 67 percent of 13 to 17 year olds in the US use the app.

TikTok is fighting against the new scrutiny. The app's chief executive wrote to senators in July to "set the record straight" about the app's data practices. TikTok's lobbyist, Michael Beckerman, went on CNN to defend the company.

Mr. Beckerman said that the data collection of TikTok was very minor. The app plans to store all of its data in the US in order to reduce security concerns. He did not say when.

The policy around apps that could expose data to foreign adversaries may be about to change. A draft of an executive order that would give the government more power was circulating earlier this year. Guidance for a committee that vets transactions involving foreign companies is expected to be issued soon by the Biden administration. It is looking at ways to review whole classes of potentially risky deals instead of approaching them individually.

The Biden administration is focused on the challenge of certain countries, including China, seeking to leverage digital technologies and Americans' data in ways that present unacceptable national security risks. Additional potential actions are being reviewed by the administration.

In 2020 Mr. Trump ordered ByteDance to sell the app to an American firm or it would be removed from the app stores. The deal to sell part of the app toOracle never came to fruition. The federal courts ruled that Mr. Biden and Mr. Trump were wrong to block the Chinese-owned apps.

The government continues to try to reduce the risks associated with TikTok. The app and the committee on foreign investment in the United States have been quietly negotiating a resolution to the government's concerns. TikTok plans to store all of its user data in the United States, instead of in Singapore and Virginia as it had previously stated.

Around 10 TikTok employees have seen the draft agreement between the company and the government, reflecting the closely held nature of the negotiations.

A spokesman for the Treasury Department, which oversees the committee on foreign investment, wouldn't comment on TikTok.

The Commerce Department has the power to review risks from foreign owned apps. The agency was staffed up for the Biden administration.

Paul Triolo is a senior vice president for China at Albright Stonebridge Group.

There were measures to protect Americans' sensitive data from collection and utilization by foreign adversaries.

Lawmakers and the administration are talking about TikTok. Mr. Warner said he had been contacted by the leadership of TikTok.

Legislators said they were still concerned. When Mr. Beckerman testified at a congressional hearing about children's online safety, hedanced around the relationship with ByteDance. Mr. Beckerman didn't lie.

The app's employees in China have recently been able to access Americans' data, according to a report. The company tried to downplay it's Chinese ownership.

Brendan Carr, a Republican member of the F.C.C., asked Apple and Google to remove TikTok from their app stores. In October of last year, he called for the F.C.C. to review the risks associated with the use of drones.

It was appropriate for Mr. Carr to speak up. Mobile apps are not regulated by the F.C.C.

The letter wasn't commented on by the company. There was no response from Apple about the message. The executive wrote that the company was keeping a close eye on the situation.

Washington is likely to remain uneasy over TikTok. The app is owned by a Chinese company and any use of it should be done with that in mind.

Emily gave reporting.