NEW YORK (AP) — A group of teachers asked the U.S. Supreme Court on Thursday for an emergency injunction blocking implementation of New York City’s COVID-19 vaccine mandate for public schools staff.

The city has given its roughly 148,000 school employees until 5 p.m. Friday to get at least their first vaccine shot, or face suspension without pay when schools open on Monday.

An original deadline earlier this week was delayed by a legal challenge. A federal appeals panel decided Monday that the nation’s largest school district could go ahead with the mandate.

An email was sent to City Hall seeking comment.

New York City Mayor Bill de Blasio has said he is confident courts will uphold the city’s efforts to exclude unvaccinated staff from school buildings, where they might infect co-workers or children too young to get the shots.

The battle over the safety of city classrooms is occurring as the state of New York is sparring in court with opponents of its vaccine mandate for workers at hospitals and nursing homes.

Courts allowed the mandate to go forward, but a federal judge in central New York has temporarily barred employers from enforcing it against people who have religious objections to getting the shots. Only a small slice of health care workers have sought a religious exemption.

The 2nd U.S. Circuit Court of Appeals in Manhattan issued an order Thursday that the stay on enforcement against people with religious objections will remain in effect until an appeal is resolved. It scheduled arguments for Oct. 14.

More than 15,000 nursing home patients have died in New York during the pandemic. Health officials have said many of those patients were probably infected by nursing home staff before vaccines became available.