With federal government employees facing a Monday deadline to provide proof of vaccination against COVID-19, the Biden administration says the vast majority of those workers have already complied with the mandate.

The Associated Press, citing an unnamed Biden administration official, reports that 90% of federal employees have provided proof of vaccination ahead of Monday's deadline.

A U.S. official said the vast majority of federal workers are fully vaccinated and that a smaller number have pending or approved exceptions to the mandate.

In September, Biden issued an order that required all federal employees to get a COVID-19 shot and provide proof by Nov. 22. The mandate did not provide a test-out option, except for those who received a medical or religious exemption.

Last week, White House press secretary Jen Psaki told reporters that the Biden administration wasn't concerned about a lack of compliance.

"We don't see it as a cliff," Psaki said Friday, according to NPR.

The federal vaccine mandate was part of a six-pronged plan Biden introduced earlier this fall to boost vaccinations and fight back against COVID-19.

Another aspect of the plan, a vaccine mandate for companies that employ more than 100 people, is currently tied up in litigation. OSHA has said it will follow a court order and not take steps to implement the mandate right now but "remains confident in its authority to protect workers in emergencies."

Biden has already implemented a vaccine mandate for those working in the Department of Defense.