- TikTok is the most downloaded app in the world. Known for short viral videos, it has tens of millions of users in the US.

- I'm so over these gas prices--

CAITLIN BURKE (VOICEOVER): In order to operate successfully, TikTok collects a lot of data. It tracks account information, search history, any content created through the platform, along with user's locations and behavioral information. Companies like Facebook and Google collect similar data, but there's one major difference-- TikTok is based in China.

- China has a national security law that compels every entity within its jurisdiction to aid its espionage and what they view as their national security efforts.

CAITLIN BURKE (VOICEOVER): This means Chinese companies are required to make all data they collect available to the Chinese Communist Party-- no exceptions. Brendan Carr, a commissioner at the Federal Communications Commission, says that includes all the personal information TikTok's been gathering on millions of Americans.

BRENDAN CARR: At the FCC, we've also taken a look at other entities beholden to the CCP, whether it's Huawei, ZTE, China Mobile. And we see just a history of nefarious conduct, from business industrial espionage to blackmail. So there's a lot of reasons to be concerned-- not about the videos but the underlying data going back en masse to China.

CAITLIN BURKE (VOICEOVER): An investigation into the national security implications of TikTok was first launched by the Treasury Department back in 2019. Then, in 2020, President Donald Trump threatened to ban the entertainment platform if it didn't sell itself to a US company.

- Bye-bye!

CAITLIN BURKE (VOICEOVER): Through it all, TikTok maintained it had never shared data with the Chinese government and insisted the information of American users was secure, being handled only by US-based teams. Then, in June, BuzzFeed got access to a collection of leaked tapes from internal meetings at TikTok, and they told a completely different story.

- They had people inside TikTok saying everything is seen in China. They had a master admin person who, again, was disclosing that there was almost no checks on what could go back there.

CAITLIN BURKE (VOICEOVER): TikTok went on damage control and recently assured concerned Republican lawmakers that new steps are being taken to further secure American data, including the transition to a US-based cloud services provider that they say will soon be used to operate the app as well as store American users' personal information.

While it sounds like a step in the right direction, TikTok's CEO also admitted some China-based engineers will still require access to the app, which by law grants that same access to Beijing.

- With that data, China is able to feed it into its artificial intelligence systems, is also perhaps able to compromise America.

CAITLIN BURKE (VOICEOVER): A key part of the work that will still need to be done in China involves TikTok's algorithm. China expert and author Gordon Chang says that's the biggest security concern of all.

- Through the control of the algorithm, China is able to influence American public opinion. We know that in 2020, the Chinese military used TikTok to incite violence on American streets. TikTok glorifies drug usage in America. And there are other things that they've been doing to interfere in our political process.

CAITLIN BURKE (VOICEOVER): In a rare show of bipartisan cooperation, lawmakers are now saying enough is enough.

- To have this kind of information, in a sense, be vacuumed off a TikTok into the Communist Party of China and what they have been doing with them-- a lot of technology and data acquisition scares the dickens out of me. It's time that we put a halt to this right now.

CAITLIN BURKE (VOICEOVER): The Senate Intelligence Committee recently sent a letter to the Federal Trade Commission requesting an investigation be launched into TikTok. Chairman of the committee, Senator Mark Warner, says he believes the evidence against the company is overwhelming.

- Senator Rubio and I have said, all right, Federal Trade Commission, this completely falls into the area of a deceptive practice. That's what we have a law to prevent. And you need to do the investigation.

CAITLIN BURKE (VOICEOVER): Meanwhile, the heads of the FBI and the United kingdom's MI5 recently issued a very clear warning about the threat posed by China.

- The most game-changing challenge we face comes from the Chinese Communist Party. It's covertly applying pressure across the globe. This might feel abstract, but it's real, and it's pressing. We need to talk about it. We need to act.

- Senator Warner says one step lawmakers can take immediately involves passing data privacy legislation. He points out this may be the last bipartisan issue that can be addressed ahead of midterms. Caitlin Burke, CBN News, Washington.