Federal Trade Commission Chair Lina Khan is facing new pressure from top Senate Intelligence leaders to investigate TikTok after new reports that the company shares US data with China-based workers.

In a letter to Khan on Tuesday, Sens. Mark Warner (D-VA) and Marco Rubio (R-FL), Senate Intelligence Committee leaders, called on the FTC to open an investigation into TikTok’s data security practices. The call comes after a June BuzzFeed News report detailed how China-based ByteDance engineers had access to TikTok’s US data as late as January 2022.

“In light of repeated misrepresentations by TikTok concerning its data security, data processing, and corporate governance practices, we urge you to act promptly on this matter,” the senators wrote.

The senators’ latest call for an investigation comes amid a new wave of regulatory skepticism against TikTok. After the BuzzFeed report was released last month, Brendan Carr, a Republican on the Federal Communications Commission, asked Apple and Google to remove TikTok from their app stores. Later, a bipartisan group of senators wrote to TikTok’s CEO, Shou Zi Chew, demanding answers regarding the app’s data security practices.

On Friday, Chew responded to US lawmakers, confirming that China-based employees could access US user data. Chew also explained that TikTok was working with Oracle to implement “new advanced data security controls that we hope to finalize in the near future.”

Since 2020, government officials have accused TikTok of sharing US user data with the Chinese government, effectively allowing Chinese officials to track and surveil Americans. TikTok has tried to quell lawmaker concerns, but Chew’s latest letter has prompted even more criticism.

In a Tuesday statement, Warner said, “For years, TikTok has assured lawmakers that user data – and business operations – were effectively firewalled from the People’s Republic of China.” He continued, “It’s a real concern when major communications apps are subject to authoritarian government requests.”

In a statement last week, Sen. Marsha Blackburn (R-TN) called for TikTok to testify before Congress in light of recent reports.

“TikTok’s response confirms that our fears regarding CCP influence within the company are well-founded,” Blackburn said. “They should have come clean from the start but instead tried to shroud their work in secrecy. Americans need to know that if they are on TikTok, Communist China has their information. TikTok needs to come back and testify before Congress.”