Alphabet Inc’s Google told its employees they would lose pay and eventually be fired if they do not follow its COVID-19 vaccination rules, CNBC initially reported on Tuesday, citing internal documents.

A memo circulated by leadership said employees had until Dec. 3 to declare their vaccination status and upload documentation showing proof, or to apply for an exemption for a medical or a religious reason. The company said after that date it would start contacting employees who hadn’t uploaded their status or were unvaccinated, as well as those whose exemption requests weren’t approved.

Employees who have not complied with the vaccination rules by Jan. 18 will be placed on “paid administrative leave” for 30 days, followed by “unpaid personal leave” for up to six months and an eventual termination.

“we’re committed to doing everything possible to help our employees who can get vaccinated do so, and firmly stand behind our vaccination policy.” Google officials responded after being asked about the new regulations.

While much of the tech industry continues to delay return-to-work plans and companies large and small prepare for an uncertain future, Google is requiring its workforce to eventually come into physical offices three days a week at some point in 2022. And it’s showing limited patience for those who refuse to get vaccines, which have been widely available for months.

The vaccine mandate has not been accepted by all Google employees. Several hundred workers have signed and circulated a manifesto opposing the company’s requirements, which leadership said would apply to all employees, even those working from home, who engage directly or indirectly with federal government contracts.

Employees placed on unpaid personal leave will be able to keep their benefits for the first 92 days, the memo released by the company said. If after six months they still aren’t in compliance with the mandate, “their employment with Google will end.”