The Biden administration on Monday said it would give federal contractors more room to enforce a mandate that their employees be vaccinated against COVID-19 by Dec. 8.

The shift in the administration’s position, announced through updates on the administration’s Safer Federal Workforce website, follows pushback by some Republicans in Congress and warnings from the contractor community about the mandate or at least a lack of flexibility in implementing it. The mandate does allow for religious and medical exemptions.

The new compliance measures from the administration say that the “contractor should determine the appropriate means of enforcement with respect to its employee at a covered contractor workplace who refuses to be vaccinated and has not been provided, or does not have a pending request for an accommodation.”

Defense contractor Lockheed Martin [LMT] said it is maintaining its current approach to fulfilling the vaccine mandate.

“As we have done throughout the pandemic, we continue to follow federal, state and local mandates, including those requiring vaccinations,” the company’s statement said. “We also use other best practices to mitigate risks and protect the health and well-being of our employees and partners, while ensuring we meet our commitments to national security.”

The National Defense Industrial Association said on Nov. 1 that it is reviewing the new guidance and that it was preparing to listen to an Office of Management and Budget call on the guidance that afternoon.

“We’re still sourcing feedback from our members on the new guidance,” NDIA spokeswoman Evamarie Socha wrote in an email. “We haven’t heard anything on the ‘relaxation’ of the Dec. 8 guidance. After Dec. 8, there is already a limited exception for an agency head to approve a 60-day exception for ‘urgent, mission-critical need’ for a covered employees to begin work on a contract or at a worksite before becoming fully vaccinated.”

The Safer Federal Workforce Task Force suggests that contractors could follow an enforcement model being used by federal agencies that encourages vaccine compliance through efforts such as counseling and education, and, if that goes nowhere, take “additional disciplinary measures if necessary.”

The guidance doesn’t suggest that contractor employees who fail to be vaccinated by the deadline be fired, at least not immediately.

“Removal occurs only after only after continued noncompliance,” it says.

Contractor employees who are not vaccinated and who work at federal sites could be denied entry by a particular agency based on the agency’s workplace rules, the guidance says.

Failure by contractors to comply with the vaccine mandate could result in termination of contracts, under President Biden’s executive order in September. However, the updated guidance tells agencies to work with their contractors that are demonstrating “good faith” to help them overcome vaccine compliance issues with their workers.

But, if a contractor isn’t working toward employee compliance, “significant actions, such as termination of the contract, should be taken,” the guidance says.