Dozens of New York City teachers placed on unpaid leave for using fake coronavirus vaccine cards

Dozens of New York City Education Department employees are being placed on unpaid leave as of Monday for submitting fake coronavirus vaccine cards.

"Fewer than 100″ employees submitted the fake vaccination cards, the DOE said Friday. A union official estimated about 70 employees were impacted.

The United Federation of Teachers, the union representing educators in the city, is preparing to challenge the move, saying some teachers claim they were wrongly accused and placing them on unpaid leave violates "the basic notion of due process."

"It is wholly improper for the DOE to unilaterally remove UFT members from the payroll based on mere conjecture that vaccination documentation is fraudulent," Beth A. Norton, general counsel for UFT, wrote in a letter to the city.

"The UFT demands that the DOE immediately rescind the aforementioned notices and confirm by the close of business April 22, 2022 that the affected UFT bargaining unit members will remain on the payroll on April 25, 2022 and thereafter," the letter added. "Should the DOE fail to comply with this demand and the due process procedures, the UFT is prepared to initiate litigation to challenge the DOE’s improper actions."

The Department of Education defended its actions in a statement.

"Fraudulent vaccination cards are not only illegal, they also undermine the best line of protection our schools have against COVID-19 -- universal adult vaccination," The Education Department said in a statement. "We immediately moved to put these employees -- fewer than 100 -- on leave without pay."

New York City has engaged in a prolonged legal battle with teachers over its vaccine mandate. The mandate went into effect on Oct. 4, 2021, at the behest of then-Mayor Bill de Blasio. The city required all public school teachers -- in the largest school system in the country -- to receive at least one dose of the vaccine.

The city said 95% of staffers had complied with the rule by Oct. 4.

But a legal battle raged on in the courts even after the mandate went into effect, with a group of teachers appealing all the way to the Supreme Court. Just this week, the nation's highest court refused to hear the case without explanation.

ABC News' Mark Osborne contributed to this report.