You'll see stories of unvaccinated patients in hospitals, as they're lying in bed dying from Covid-19, they're asking, 'Doc, can I get the vaccine?' The doctors have to say, 'Sorry, it's too late.'"

In his sternest approach yet to pushing Americans to get vaccinated, the President bluntly argued that if you are unvaccinated, "You present a problem to yourself, to your family and to those with whom you work."

Biden said every federal government employee and on-site contractor will be asked to attest to their vaccination status.

Employees who have not been vaccinated "will be required to wear a mask on the job no matter their geographic location, physically distance from all other employees and visitors, comply with a weekly or twice weekly screening testing requirement, and be subject to restrictions on official travel," the White House said ahead of Biden's speech.

The federal employee vaccination requirement is not a mandate, officials have insisted, and most federal employees who do not get vaccinated will not lose their jobs as a result, CNN previously reported.

But the decision nonetheless marks a pivot away from encouraging Americans to get vaccinated in their own time and stepping toward placing the onus on unvaccinated individuals.

Other efforts the administration debuted Thursday to incentivize vaccinations included expanding paid leave for employees who take time off to get themselves and their family members vaccinated.

Those unable or unwilling to do so will "be required to wear a mask, physically distance, comply with a regular testing requirement and be subject to official travel restrictions," Jamal Brown, deputy Pentagon press secretary, said in a statement.

The department is also considering adding the Covid vaccine to the list of required vaccines for military personnel.

"Secretary (of Defense Lloyd) Austin will begin consulting our medical professionals, as well as the Joint Chiefs of Staff, to determine how and when to make recommendations to the President with respect to adding the COVID-19 vaccines to the full list of requirements for military personnel," Brown said.

The President on Thursday also called on school districts nationwide to host at least one pop-up vaccination clinic over the coming weeks in an effort to get more kids 12 and older vaccinated.

Responding to reporter questions after his remarks, the President said he didn't know yet whether the federal government had the power to require vaccines.

"It's still a question whether the federal government can mandate the whole country" require vaccines, he said, adding that he expects the vaccines will be fully approved by the US Food and Drug Administration by the fall.

"That's not an authority that we're exploring at all," Zients said on "The Situation Room."

On Monday, the Justice Department determined that federal law doesn't prohibit public agencies and private businesses from requiring Covid-19 vaccines -- even if the vaccines have only emergency use authorization so far.

But several groups representing federal workers across the government are already raising concerns about the requirement for their personnel, including groups representing federal law enforcement officers, IRS managers and members of the US Border Patrol, among others.

Other groups, like the International Federation of Professional and Technical Engineers, have come out in support.

The goal of the requirement, Biden aides have said, is to render being unvaccinated so burdensome that those who haven't received shots will have little choice other than to get them.

And some states, including New York, have also said government employees must either prove they've been vaccinated or be tested weekly.

The White House had previously indicated it would support private companies' decisions to mandate Covid-19 vaccinations, but Biden took it a step further on Thursday, saying that he'd like to see companies, states and schools move in the direction of requiring Covid-19 vaccination.

Dr.

Rochelle Walensky, director of the CDC, said Wednesday on CNN that health passes for the fully vaccinated, such as those used in parts of Europe, "may very well be a path forward."

But the President appeared to put that responsibility on businesses -- not the federal government -- on Thursday.

"My guess is that if we don't start to make more progress, a lot of businesses and a lot of enterprises are going to require proof (of vaccination) or you're not going to be able to participate," Biden said.

The prevalence of the highly contagious Delta variant in the US and low vaccine uptake have led to the federal government to take a number of steps to further mitigate the spread of Covid-19.