At least 71 people were killed in Israel’s attack on Tehran’s Evin prison, a notorious facility where many political prisoners and dissidents have been held, 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. It was not possible to independently verify the claim.

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.

On the day of the attack, the New York-based Center for Human Rights in Iran criticized Israel for striking the prison, seen as a symbol of the Iranian regime's repression of any opposition, saying it violated the principle of distinction between civilian and military targets.

Prison Attack Came Near the End of 12 Days of Strikes
Over the 12 days before a ceasefire was declared, Israel claimed it killed around 30 Iranian commanders and 11 nuclear scientists, while hitting eight nuclear-related facilities and more than 720 military infrastructure sites. More than 1,000 people were killed, including at least 417 of them civilians, according to the Washington-based Human Rights Activists group.

In retaliation, Iran fired more than 550 ballistic missiles at Israel, most of which were intercepted, but those that got through caused damage in many areas and killed 28 people.

Abbas Araghchi, Iran's foreign minister, said in a Saturday letter to United Nations officials that the international body should recognize Israel and the United States “as the initiators of the act of aggression” against Iran over the war and that their targeting of sovereign country and its people should require “compensation and reparation."

“The Security Council should also hold the aggressors accountable and prevent the recurrence of such heinous and serious crimes to enable it to maintain international peace and security,” Araghchi said in the letter obtained by The Associated Press.

At the same time, advocates have said that Iran was legally obligated to protect the prisoners held in Evin, and slammed authorities in Tehran for their “failure to evacuate, provide medical assistance or inform families” following the attack.

Jahangir said some of the injured were treated on-site, while others were taken to hospitals.

Iran had not previously announced any death figures, though on Saturday, it confirmed that top prosecutor Ali Ghanaatkar -- whose prosecution of dissidents, including Nobel Peace Prize winner Narges Mohammadi, led to widespread criticism by human rights groups -- had been killed in the attack.

He was one of about 60 people for whom a massive public funeral procession was held on Saturday in Tehran, and he was to be buried at a shrine in Qom on Sunday.