- We're going to turn now to the heated showdown on Capitol Hill today. The CEO of TikTok under fire from lawmakers on both sides of the aisle over your personal information, your privacy, and over national security concerns involving the massively popular TikTok app. The CEO trying to fend off a possible ban today on the Hill, promising that there's a firewall protecting your personal information from the Chinese government. But you're about to see the back and forth. Lawmakers were not convinced. Here's our senior congressional correspondent, Rachel Scott, on the Hill tonight. RACHEL SCOTT: Today, the CEO of TikTok swarmed by cameras on Capitol Hill. Lawmakers from both parties, unloading right from the start. CATHY MCMORRIS RODGERS: TikTok talk surveils us all. And the Chinese Communist Party is able to use this as a tool to manipulate America as a whole. Your platform should be banned. RACHEL SCOTT: For more than five hours, CEO Shou Chew defended the wildly popular app and its Chinese parent company ByteDance, insisting the platform had taken steps to protect the data of its millions of American users. - There are more than 150 million Americans who love our platform. And we know we have a responsibility to protect them. We will firewall protect the US data from unwanted foreign access. RACHEL SCOTT: But there are serious questions about whether the Chinese government would ever respect that firewall. Lawmakers weren't buying it. - You spoke in your opening statement about a firewall relative to the data. But the Chinese government has that data. - I have seen no evidence that the Chinese government has access to that data. They have never asked us. We have not provided-- - Well, you know what? I find that, actually, preposterous. RACHEL SCOTT: One member after another grilling Chu on whether TikTok and its Chinese parent company had spied on Americans, something the Department of Justice is investigating. - Has Bytedance spied on American citizens? - I don't think that "spying" is the right way to describe it. - Chew was asked directly if he agreed with top US intelligence officials that China could use TikTok as a tool to manipulate millions of Americans. - Do you disagree with their statement? - Their statement says "could." CONGRESSMAN: So do you disagree with that? - No, I don't disagree. - Lawmakers today also raising concerns about how quickly harmful and dangerous content is able to be spread on the app. But at the same time, they recognize that millions of young Americans use TikTok every single day. So now, the White House and Congress are forced to weigh its popularity with the risk. David. DAVID MUIR: That's a question, for sure, too. Rachel Scott tonight. Rachel, thank you again.