Momentum for efforts to restrict TikTok is building in the Senate, and House lawmakers are preparing to grill the company’s CEO, as the China-founded app looks to be running out of time to persuade federal lawmakers not to limit its operations.

Two Republican senators authored a new plan to withhold taxpayer cash from supporting TikTok’s business partners, while bipartisan legislation to empower the Biden administration to ban the app enlisted six more senators on Friday.

Sens. Marco Rubio of Florida and Joni Ernst of Iowa propose …