In the wake of a major uptick in the number of measles cases reported in New York City, officials have ordered the closure of two religious Jewish schools in Brooklyn until they comply with new Health Department orders requiring that children be vaccinated against the contagious illness.

New York City Mayor Bill de Blasio declared a city-wide health emergency, ordering all those living or working in the Brooklyn neighborhood of Williamsburg—home to a large ultra-Orthodox Jewish population—to report for vaccinations or pay fines of up to $1,000.

Of the 423 cases of measles reported in New York since October, 348 were in Williamsburg.

The two religious schools closed for lack of compliance are Tiferes Bnos and the Talmud Torah D’Nitra preschool.

“Schools that continue to disregard our direction during the outbreak will be closed down until they can prove to the Health Department that they will comply,” said New York Health Commissioner Dr. Oxiris Barbot. “The reality is, the longer it takes schools and individuals to comply with our order, the longer this outbreak will continue.”

The Health Department had already shuttered five schools for failing to maintain vaccination and attendance records, but later gave them permission to reopen. Fifty-seven summonses have been issued for vaccination noncompliance.