A vaccine mandate won’t be finalized until Thursday, the person said. A second person familiar with the matter said a federal vaccine mandate is under strong consideration.

The plan comes amid a spike in cases fueled by vaccine holdouts, which allowed the highly contagious delta variant to spread across the country.

Biden said Tuesday he was weighing a vaccine requirement for federal workers, and he’ll deliver a speech on the U.S. fight against the pandemic on Thursday. Federal workers who do not confirm they are vaccinated may be required to wear masks, even in communities without substantial virus spread, in addition to undergoing regular tests, according to the second person.

The Biden administration laid out a series of new steps to steps to beat back the virus surge, which poses a serious political threat to the president. Biden had counted on plummeting case rates to anchor the economic recovery and his policy agenda.

The Centers for Disease Control and Prevention tightened its mask guidance on Tuesday, advising Americans to wear masks in public indoor places located in areas with substantial spread. That led the White House on Tuesday to force staff and reporters to begin covering their faces again while inside the complex, after the District of Columbia’s case rate spiked.

The vaccine mandate for federal workers also follows a decision by the Department of Veterans Affairs to require front-line health care workers to be vaccinated.

The U.S. recorded more than 71,000 new cases on Tuesday, driving the rolling seven-day average up to 59,700, according to the Bloomberg COVID-19 Tracker. The average case rate is more than four times higher than it was three weeks ago, before the delta variant became the dominant U.S. strain.

CNN and NBC News reported earlier that he would issue a vaccine mandate for federal workers.

—With assistance from Mario Parker.