At least 71 people were killed in Israel’s attack on Tehran’s Evin prison, Iran’s judiciary said on Sunday.

Judiciary spokesperson Asghar Jahangir posted on the office’s official Mizan news agency website that those killed on Monday included staff, soldiers, prisoners and members of visiting families.

The June 23 attack, the day before the ceasefire between Israel and Iran took hold, hit several prison buildings and prompted concerns from rights groups about the safety of the inmates.

It remains unclear why Israel targeted the prison, but it came on a day when the Defense Ministry said it was attacking “regime targets and government repression bodies in the heart of Tehran.”

The news of the prison attack was quickly overshadowed by an Iranian attack on a US base in Qatar later that same day, which caused no casualties, and the announcement of the ceasefire.

Jahangir did not break down the casualty figures but said the attack had hit the prison’s infirmary, engineering building, judicial affairs and visitation hall, where visiting family members were killed and injured.