A federal appeals panel ruled Monday that New York City’s vaccine mandate for all adult staffers at its public schools can proceed as planned.

The decision reverses one made over the weekend that paused the order, The New York Times reported.

But lawyers for teachers unions say they will ask the U.S. Supreme Court to intervene, according to The Associated Press.

Mayor Bill de Blasio ordered more than 150,000 city public school educators and staff to get at least one dose of a COVID-19 vaccine by midnight Monday. The U.S. Court of Appeals for the 2nd Circuit had delayed the deadline under Friday, but a three-judge panel took up the issue early after arguments were submitted from both sides.

Vaccination rates are already high among principals (97%) and teachers (95%) in New York City, and 87% of non-teaching staff had at least one shot, the Times reported.

Those numbers came after about 8,000 employees were vaccinated over the weekend to get compliant before the deadline, according to the Times.

Unions for New York City Public Schools had argued staffing was already short, so the vaccine mandate would create a larger crunch. The Department of Education mandate might ultimately become a model for other city employees in the future.

Attorney Mark Fonte, who brought the lawsuit on behalf of teachers and others, said in a statement that he and attorney Louis Gelormino were immediately petitioning the Supreme Court to intervene.

“As of this moment the mandate is in place,” he said, adding he and Gelormino were “dismayed and disappointed by this turn of events.”

“With thousands of teachers not vaccinated the city may regret what it wished for. Our children will be left with no teachers and no security in schools.”

The lawyers wrote the city’s order will “leave teachers and paraprofessionals without the resources to pay rent, utilities, and other essentials. The harm is imminent.”

They said the mandate would leave thousands of New York City children in the nation’s largest school district without their teachers and other school workers.

“Imminent and irreparable harm exists,” the lawyers wrote.

Information from The Associated Press was used in this report.