WASHINGTON (AP) — U.S. lawmakers grilled the CEO of TikTok over data security and harmful content Thursday, responding skeptically during a tense committee hearing to his assurances that the hugely popular video-sharing app prioritizes user safety and should not be banned.

Shou Zi Chew's rare public appearance came at a crucial time for the company, which has 150 million American users but is under increasing pressure from U.S. officials. TikTok and its Chinese parent company, ByteDance, have been swept up in a wider geopolitical battle between Beijing and Washington over trade and technology.

In a bipartisan effort to reign in the power of a major social media platform, Republican and Democratic lawmakers pressed Chew on a host of topics, ranging from TikTok's content moderation practices, how the company plans to secure American data from Beijing, and its spying on journalists.

"Mr. Chew, you are here because the American people need the truth about the threat TikTok poses to our national and personal security," Committee Chair Cathy McMorris Rodgers, a Republican, said in her opening statement.

Chew, a 40-year-old Singapore native, told the House Committee on Energy and Commerce that TikTok prioritizes the safety of its young users and denied it's a national security risk. He reiterated the company's plan to protect U.S. user data by storing it on servers maintained and owned by the software giant Oracle.

"Let me state this unequivocally: ByteDance is not an agent of China or any other country," Chew said.

TikTok has been dogged by claims that its Chinese ownership means user data could end up in the hands of the Chinese government or that it could be used to promote narratives favorable to the country's Communist leaders.

In 2019, the Guardian reported that TikTok was instructing its moderators to censor videos that mention Tiananmen Square and images unfavorable to the Chinese government. The platform says it has since changed its moderation practices.

ByteDance admitted in December that it fired four employees last summer who accessed data on two journalists and people connected to them while attempting to uncover the source of a leaked report about the company.

For its part, TikTok has been trying to distance itself from its Chinese origins, saying 60% percent of ByteDance is owned by global institutional investors such as Carlyle Group.

"Ownership is not at the core of addressing these concerns," Chew said.

China has also said it would oppose any U.S. attempts to force ByteDance to sell the app.

In one of the most dramatic moments, Republican Rep. Kat Cammack played a TikTok video that showed a shooting gun with a caption that included the House committee holding the hearing, with the exact date before it was formally announced.

"You expect us to believe that you are capable of maintaining the data security, privacy and security of 150 million Americans where you can't even protect the people in this room," Cammack said.

TikTok spokesperson Ben Rathe said the company on Thursday removed the violent video aimed at the committee and banned the account that posted it.

Chew also noted the failure of U.S. social media companies to address the very concerns for which TikTok was being criticized.

"American social companies don't have a good track record with data privacy and user security," he said. "Look at Facebook and Cambridge Analytica, just one example."

As the Energy and Commerce committee questioned Chew, Secretary of State Anthony Blinken was questioned about the threat TikTok poses at a separate committee hearing Thursday. Asked by Rep. Ken Buck, a Republican of Colorado, if the platform is a security threat to the United States, Blinken said: "I believe it is."

"Shouldn't a threat to United States security be banned?" Buck responded.

"It should be ended one way or another. But there are different ways of doing that," Blinken responded.

Committee members also showed a host of TikTok videos that encouraged users to harm themselves and commit suicide. Many questioned why the platform's Chinese counterpart, Douyin, does not carry the same controversial and potentially dangerous content as the American product.

Chew responded that it depends on the laws of the country where the app is operating. He said the company has about 40,000 moderators that track harmful content and an algorithm that flags material.

Wealth management firm Wedbush described the hearing as a "disaster" for TikTok that made a ban more likely if the social media platform doesn't separate from its Chinese parent. Emile El Nems, an analyst at Moody's Investors Service, said a ban would benefit TikTok rivals YouTube, Instagram and Snap, "likely resulting in higher revenue share of the total advertising wallet."

To avoid a ban, TikTok has been trying to sell officials on a $1.5 billion plan, Project Texas, which routes all U.S. user data to Oracle. Under the project, access to U.S. data is managed by U.S. employees through a separate entity called TikTok U.S. Data Security, which is run independently of ByteDance and monitored by outside observers.

As of October, all new U.S. user data was being stored inside the country. The company started deleting all historic U.S. user data from non-Oracle servers this month, in a process expected to be completed this year, Chew said.

Republican Rep. Dan Crenshaw noted that regardless of what the company does to assure lawmakers it will protect U.S. user data, the Chinese government can still have significant influence over its parent company and ask it to turn over data through its national security laws.

Congress, the White House, U.S. armed forces and more than half of U.S. states have already banned the use of the app from official devices.

But wiping away all the data tracking associated with the platform might prove difficult. In a report released this month, the Cybersecurity company Feroot said so-called tracking pixels from ByteDance, which collect user information, were found on 30 U.S state websites, including some where the app has been banned.

Other countries including Denmark, Canada, Great Britain and New Zealand, along with the European Union, have already banned TikTok from government-issued devices.

A complete TikTok ban in the U.S. would risk political and popular backlash.

The company sent dozens of popular TikTokers to Capitol Hill on Wednesday to lobby lawmakers to preserve the platform. And a dozen civil right and free speech organizations, including the American Civil Liberties Union and PEN America, have signed a letter opposing a wholesale TikTok ban, arguing it would set a "dangerous precedent for the restriction of speech."

David Kennedy, a former government intelligence officer who runs the cybersecurity company TrustedSec, said he agrees with restricting TikTok access on government-issued phones but that a nationwide ban might be too extreme.

"We have Tesla in China, we have Microsoft in China, we have Apple in China. Are they going to start banning us now?" Kennedy said. "It could escalate very quickly."

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Associated Press reporters Kelvin Chan in London and Barbara Ortutay in San Francisco contributed to this story.

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This story has been corrected to show Oracle is a software giant, not a server giant.