Leading Haredi Rabbi Yosef Elyashiv published a letter on Tuesday criticizing his counterpart Shas spiritual leader Rabbi Ovadia Yosef's approval of conversions officiated by the Israel Defense Forces, calling all those converted by the state gentiles.

"Everyone knows that there gentiles do not intend to take upon themselves a thing from the essence of the religion, neither the Sabbath, kashrut nor family purity laws. And everyone knows…. That the gentiles do not intend to embrace Judaism," Elyashiv wrote in a letter signed by 17 ultra-Orthodox rabbis.

"We turn to everyone who can stop this terrible desecration, and to close the divider that has been breached," the letter wrote.

The letter did not mention Rabb Ovadia's name, but the letter was concluded with a statement directed at him saying "may the blessed lord place wisdom in the hearts of the misguided."

Yosef, a former chief military rabbi himself, said following his ruling that his decision was informed by his own knowledge and experience with the military rabbinate.

Under current practice, Israel recognizes only conversions performed by Orthodox rabbis inside Israel, but people converted by non-Orthodox rabbis outside the country are automatically eligible for Israeli citizenship like other Jews. The legislation would give Israel's chief rabbinate the legal power to decide whether any conversion is legitimate.

The group most likely to suffer would be immigrants who converted to Judaism abroad and could now be denied Israeli citizenship.