U.S. Sen. Michael Bennet said he told TikTok CEO Shou Zi Chew that the app poses an “unacceptable risk to U.S. national security,” poisons teenagers’ mental health, and harms a generation of Americans.

Bennet’s office said he told Chew his misgivings during a meeting in which they held a “frank conversation.”

“Mr. Chew and I had a frank conversation, and I appreciate his time. But I remain fundamentally concerned that TikTok, as a Chinese-owned company, is subject to dictates from the Chinese Communist Party and poses an unacceptable risk to U.S. national security,” Bennet said in a statement.

The senator added: “Mr. Chew and I also discussed the poisonous influence of TikTok’s algorithms on teen mental health, and I urged him to consider his platform’s harm to a generation of Americans.”

Bennet earlier urged Apple and Google to remove TikTok from their app stores immediately.

“Like most social media platforms, TikTok collects vast and sophisticated data from its users, including faceprints and voiceprints. Unlike most social media platforms, TikTok poses a unique concern, because Chinese law obligates ByteDance, its Beijing-based parent company, to ‘support, assist, and cooperate with state intelligence work,'” Bennet wrote in a letter to CEO Tim Cook and Alphabet and Google CEO Sundar Pichai. 

Bennet wrote that TikTok’s extensive reach in the U.S. is dangerous, arguing that the app’s “aggressive data collection” and “obligations under Chinese law threaten U.S. security.”