The illegal tunnel discovered under a historic Brooklyn synagogue compromised the stability of several structures surrounding the religious complex, prompting an order to vacate as well as citations against its owners, city officials said.

Inspectors with New York City’s building safety agency uncovered a tunnel that was 60 feet (18.3 meters) long and 8 feet (2.4 meters) wide beneath the Chabad-Lubavitch global headquarters in Crown Heights. It extended under several buildings in the vicinity, connecting between openings cut into basement walls.

The excavation work was done without approval by the Department of Buildings, Andrew Rudansky, a spokesperson for the agency, said in an email to the Associated Press on Wednesday.

The findings came after a two-day investigation into the structural stability of the complex, an internationally revered Hasidic Jewish site that draws thousands of visitors each year.

Rabbi Motti Seligson, a spokesperson for Chabad, said the underground passage was built by a group of “young agitators” seeking unauthorized access to the synagogue. When Chabad officials attempted to seal the openings on Monday, a faction of worshippers staged a protest, refusing to leave the tunnel and eventually brawling with police. Nine people were arrested, including some who used crowbars to rip off the synagogue’s wood paneling, according to a police report.

It was not immediately clear when the tunnel was constructed or what it was intended to accomplish. Some members of the community said they were hoping to fulfill the “expansion” plan of the former head of the Chabad movement, Rebbe Menachem Mendel Schneerson. A faction of Chabad believes that Schneerson is the messiah and is still alive.

Levi Huebner, an attorney for five of the men arrested, said his clients may have suffered from a “little naivete,” but had no intention of harming the building structurally.

“I’m 100% confident they wouldn’t go near anything, do anything to disrupt the foundation of the synagogue in any way whatsoever,” Huebner said.

City inspectors said the excavation had undermined the stability of two single-story structures behind the synagogue. An adjacent two-story brick building containing offices and lecture halls used by Chabad was also ordered vacated due to the illegal removal of fire-rated walls in the building’s cellar. They said the building containing the synagogue was not destabilized. It remains closed to worshippers.

Rundansky said the department has cited the synagogue for the illegal excavation work that created the tunnel, but confirmed that the owners are taking the appropriate steps to fix it.