As the years-long investigation into the city's ultra-Orthodox Jewish schools continues to stall, the state education department on Tuesday released new guidelines that could force private schools, including yeshivas, to improve the quality of secular instruction offered to students.

Issued by Education Commissioner MaryEllen Elia, the new guidance will kick off district-led review processes next year to determine whether nonpublic schools are offering "substantially equivalent education." Those that are not will be given extra time and assistance to reform their academics. If they do not improve, the schools would lose access to state services like textbooks, special education, and transportation, Elia said.

Parents would be told to send their kids elsewhere, and students could "be considered truant" if they continue attending a noncompliant school, according to the guidelines. Eventually, the state could shut down schools that don't abide by the regulations.

"We want to ensure that all students receive the education they are entitled to under state Education Law, no matter which school they attend," Elia said.

The new regulations come amid ongoing controversy surrounding New York's ultra-Orthodox schools, which advocates say leave students—particularly high school boys—with an education based almost solely on religious studies. But efforts to investigate the schools has met fierce resistance, and NYC Schools Chancellor Richard Carranza acknowledged in a letter sent to the state this summer that a city-led probe had made little progress over three years. A month later, Governor Andrew Cuomo reportedly promised the Satmar Rebbe of Williamsburg that he "would not interfere in yeshiva education."

Naftuli Moster, founder of the Orthodox-led advocacy group Young Adults For A Fair Education, called the updated guidelines "an important step toward bringing about useful oversight of secular instruction." But he noted that the new regulations don't directly address a last-minute amendment forced through by State Senator Simcha Felder during this year's budget process, which would largely exempt the religious institutions from minimum education requirements.

It's unclear how the new guidelines would affect that law, and whether Felder, whose power in Albany was significantly reduced thanks to the Democratic takeover of the State Senate, will be able to continue shielding yeshivas from oversight. As the initial review deadline isn't until 2021—"far too long," according to advocates—it's unlikely that those questions will be cleared up anytime soon.

"We don’t believe that the yeshivas that have been stonewalling should be rewarded with even more time," Moster said in a statement. "We will continue to monitor these developments and hold those in power accountable."