The incarceration of “Prisoner X”, the high-security prisoner who committed suicide in Ayalon Prison in 2010, was made necessary by Israel’s “unique” security situation, Vice Premier and Strategic Affairs Minister Moshe Ya’alon said Saturday.

Speaking to Channel 2, Ya’alon said that owing to Israel’s “unique” reality, “extreme measures” such as the conditions under which Ben Zygier was incarcerated were not only necessary, but even constituted pikuach nefesh — the Jewish imperative to save lives, even if religious laws are broken in the process.

Ya’alon stressed that Israel is no “benighted” state, and does not incarcerate prisoners under assumed names without notifying the legislature and the prisoner’s family.

Ya’alon refused to acknowledge that the mysterious Melbourne-born prisoner was a Mossad agent or to disclose the deed Zygier had allegedly committed to warrant incarceration in a solitary high-security cell, saying only that the measures were justified.

“We have to assume that if we reached such a state, it means there was a slip here that required that steps be taken by the organization under discussion… under full supervision, and after many considerations,” said Ya’alon.

Slamming the left-wing MKs who had lobbied for the publication of the story in Israeli media, Ya’alon said there were other ways to expose the matter “without harming Israel’s security.” He accused the MKs of exploiting the situation for political gain without thinking of the consequences, such as the portrayal of Israel as a “benighted, undemocratic state” and its defense establishment as unprofessional.

Asked whether the publication of the story had caused security damage, Ya’alon refused to comment on the matter in order to “refrain from endangering Israel’s security.”

However, he admitted that the Israeli defense establishment had “learned a lesson” from the incident.

Ya’alon’s comments follow an official confirmation in writing that a top-security inmate had indeed been held under an assumed name and committed suicide in 2010. Aside from Wednesday’s confirmation, few official remarks have been made on the shadowy matter.

It has been widely reported that Zygier was recruited by the Mossad after immigrating in 2000, was questioned by the Australian security authorities when back in his country of birth nine years later, was arrested in Israel in early 2010, and committed suicide in his cell at Ramle’s Ayalon Prison on December 15, 2010, aged 34. He was married to an Israeli woman and had two children.

The alleged crime that led to his incarceration has not been detailed. Nor has it been explained how he was able to kill himself in a high-security cell while under suicide watch.