Biden is expected to say federal workers must be vaccinated or face regular tests.

U.S.|Biden is expected to say federal workers must be vaccinated or face regular tests.

• July 29, 2021, 4:54 a.m. ET

President Biden on Thursday will formally announce that all civilian federal employees must be vaccinated against the coronavirus or be forced to submit to regular testing, social distancing, mask requirements and restrictions on most travel, the White House said.

The federal government employs more than 4 million Americans, all of whom will need to attest to being fully vaccinated in order to avoid wearing a mask on the job, regardless of where in the country they work, and comply with screening tests once or twice a week.

The president was also set to direct the Defense Department to study how and when to add the coronavirus vaccine to the list of required vaccinations for all members of the military. The announcement marked the first time he has suggested that a mandate could come for active-duty members of the military before any of the three federally authorized vaccines receives full approval from the Food and Drug Administration.

Mr. Biden was set to announce the new mandates at a speech in the East Room, part of an attempt to reset expectations on the health scourge that just weeks ago he thought he had under control. But now, the Delta variant is ripping through unvaccinated communities, threatening to undo the progress to stop the spread of the coronavirus made by the Biden administration in its first six months.

In response, the administration is stepping up its efforts to convince unvaccinated Americans to get their shots. Mr. Biden on Thursday will call on states, territories and local governments to pay $100 to Americans who remain unvaccinated to get their shots. And the administration announced Thursday that small- and medium-sized businesses will now be reimbursed for offering their employees paid leave to get their family members, including their children, vaccinated.

Some experts, especially in the early days of the vaccination campaign, have expressed concern over the idea of paying people to get vaccinated, worrying that it could be perceived as out of step with messaging that vaccines bring enormous benefits on their own.

Mr. Biden will also call on school districts across the country to host at least one pop-up vaccination clinic over the coming weeks, with the goal of increasing vaccination rates among children 12 and older.

The president’s move is expected to be similar to an announcement on Wednesday by Gov. Andrew M. Cuomo of New York, who said that tens of thousands of state employees would be required to show proof of vaccination or submit to weekly testing. Mr. Cuomo also said that “patient facing” health care workers at state-run hospitals would be required to be vaccinated as a condition of their employment.

Other governments around the country are beginning to put in place similar arrangements as well, as the highly contagious Delta variant has caused case numbers to balloon in recent weeks. New York City announced this week that it would require all 300,000 city employees to be vaccinated or submit to weekly testing. California also unveiled a plan to require vaccinations for state employees. The North Carolina Department of Health and Human Services will require all workers and volunteers at state-operated facilities to be fully vaccinated or receive an approved medical or religious exemption by Sept. 30, according to a statement sent to The New York Times on Wednesday. Officials had not responded to questions about whether those with exemptions will be required to undergo testing.

And the Department of Veterans Affairs will require 115,000 of its frontline health care workers to be vaccinated against the coronavirus in the next two months. But public health officials are hoping that the prospect of extra burdens for the unvaccinated will help persuade more people to get inoculated.

People familiar with Mr. Biden’s announcement said it was part of a longstanding discussion about how to bring most federal workers back to the office after nearly a year and a half in which hundreds of thousands of them worked from home because of the pandemic.

A team has been working on that plan for months, trying to juggle the concerns of employees and the need to keep the government functioning. One concern that officials confronted was how to require vaccinations without potentially prompting critical employees to quit, undermining the government’s mission.

But the president’s announcement comes as the administration is under pressure to increase the rate of vaccinations in the country. About half of all Americans have been fully vaccinated, but the number of people getting shots has slowed significantly from the early months of the year.

Karine Jean-Pierre, the deputy White House press secretary, declined on Wednesday to provide details of the president’s speech, but said that the general approach would be to give employees a choice that would hopefully encourage them to get vaccinated.

The plan, she told reporters, is aimed at “confirming vaccination status or abiding by stringent Covid-19 protocols, like mandatory mask wearing, even in communities not with high or subsequent substantial spread, and regular testing.”

Rebecca Robbins and Dan Levin contributed reporting.