China's government can use TikTok to spy on American users and push propaganda at alarming levels, senators who received a classified briefing on the social media app told Axios.

Why it matters: The senators were hesitant to give details about Wednesday's briefing, but said Americans would be frightened by TikTok's ability to access and track their personal data.

• One senator said national security officials described how China can harvest user data and weaponize it through propaganda and misinformation.
• Another lawmaker said they were told TikTok is able to spy on the microphone on users' devices, track keystrokes and determine what the users are doing on other apps.

The big picture: Senate leaders are weighing what to do with a bill that would force China-based ByteDance to sell TikTok or face a ban in the U.S. The House passed the bill overwhelmingly last week after its members received a similar security briefing.

• It's unclear whether the briefing from the FBI, Justice Department and the Director of National Intelligence office was a needle-mover for senators who may be skeptical of the bill.

What they're saying: Sen. Richard Blumenthal (D-Conn.) told Axios the briefing's "level of detail and specificity was extremely impactful."

• Sen. Ted Cruz (R-Texas) said the briefing was helpful in "bringing some members up to date with the threats that China poses through TikTok."
• "Their ability to track, their ability to spy is shocking," Sen. Eric Schmitt (R-Mo.) said.

Reality check: Such warnings from federal officials so far haven't been enough for senators to fast-track the bill.

• Sen. Mark Warner (D-Va.), chair of the Intelligence Committee, said Thursday that it would take longer than the eight days it took for the bill to clear the House because that's "just the way the Senate works."
• The legislation has been referred to the Senate Commerce Committee.
• Sen. John Hickenlooper (D-Colo.), a member of the committee, said the TikTok legislation is "something we should move faster on, not slower."