The Chinese government can use TikTok to spy on American users and spread propaganda at an alarming rate, members of the U.S. Senate who have received confidential briefings on the social media app said today. The senators would not reveal details of Wednesday's briefing but said Americans would be horrified by TikTok's ability to harvest and track their personal data.

One senator said national security officials described how China obtained user data and weaponized it with propaganda and misinformation. One lawmaker said they were told TikTok is capable of monitoring microphones on users' devices, tracking keyboard input and determining what users do on other apps.

Senate leaders are weighing what to do about a bill that would force China-based company ByteDance to sell TikTok or face a ban in the United States. The House of Representatives overwhelmingly passed the bill last week after receiving a similar security briefing. It’s unclear whether the briefings from the FBI, Justice Department and Office of the Director of National Intelligence played a significant role in reaching those senators who may have been skeptical of the bill.

Senator Richard Blumenthal said the briefing's "level of detail and specificity was extremely impactful."

Senator Ted Cruz said the briefing would help "educate some members on the latest threat posed by China through TikTok."

"Their tracking and espionage capabilities are astounding," said Sen. Eric Schmidt (R-Mo.).

But so far, those warnings from federal officials haven't been enough for senators to quickly pass the bill.

Senator Mark Warner, chairman of the Intelligence Committee, said on Thursday that the bill would take more than eight days to pass the House because that's "the way the Senate works."

The legislation has been referred to the Senate Commerce Committee. Senator John Hickenlooper (D-Colorado), a member of the committee, said TikTok legislation is "something we should speed up, not slow down."