Explained | What to know about Iran's Evin Prison

Israel's military on Monday targeted Iran's Evin prison, a notorious detention facility in Tehran, the capital, where dissidents and political prisoners are held. The detention center has long been regarded as a symbol of repression, and human rights groups and survivors say that torture and executions are routine there.

Israeli Defense Minister Israel Katz announced the attack, which came amid Israeli strikes elsewhere in Tehran. Video footage verified by The New York Times shows an explosion at the main entrance to the prison compound and damage after a blast near a second entrance.

It was unclear why Israel struck the prison. There were no immediate reports of injuries, and Iran said it still had control of the facility.

Here's what to know about the prison and the Israeli attack:

What is Evin prison?

Thousands of prisoners are held at Evin, among them hundreds of dissidents, including prominent opposition politicians, activists, lawyers, journalists, environmental activists and students. It is also used to hold prominent non-Iranian or dual-citizen prisoners, many of whom have been accused of spying.

The prison sits on a hilltop in northern Tehran at the foot of the Alborz Mountains. The compound is surrounded by electrified barbed-wire fences as well as a minefield.

How was the prison damaged?

IRNA, the Iranian state news agency, reported that projectiles had caused "damage to parts of the facility" but said the prison was "under full control."

Video footage verified by the Times shows an explosion at the entrance and rescue workers clearing debris and metal beams collapsed by the strike from a gaping hole in the entrance.

Other footage verified by the Times shows damage to buildings in the immediate aftermath of another explosion by a second entrance to the prison complex, about 600 yards from the main prison entrance. This strike appeared to be by an entrance to a visitation center.

How did Evin gain its reputation?

The prison was opened in 1971 under Shah Mohammed Reza Pahlavi. Over the next seven years, the facility came to international prominence because of what Human Rights Watch called the "horrifying conditions" in which prisoners were held by the secret police.

A 1979 revolution, set off in part by anger at the autocratic government, overthrew the shah, ushering in a theocratic regime under Ayatollah Ruhollah Khomeini. But the prison's notoriety grew.

In 1988, thousands of Evin prisoners were executed after cursory trials, according to Human Rights Watch. Many of those killed were viewed as a threat to the new Islamic government.

Several prominent Iranians were detained at Evin during the wave of protests in 2022 that followed the death of Mahsa Amini, a 22-year-old Iranian woman arrested by Iran's morality police. During the protests, a huge fire broke out at the prison. Residents nearby reported gunshots and explosions amid chants of "death to the dictator," and IRNA reported at the time that eight people had been injured. The cause of the fire remained unclear.

In April, the European Union placed the head of the prison, Hedayatollah Farzadi, under sanctions.

What are conditions like at the prison?

Former prisoners have described long interrogations, torture, rape, psychological humiliation, solitary confinement and other examples of harsh treatment and abuse.

Executions at the prison have often been conducted by hanging, they say. Female prisoners who have been tortured have also then been denied adequate medical care, according to Amnesty International.

Cecilia Sala, an Italian journalist who was detained in Iran in December and held at the prison before being released, said her cell had two blankets but no mattress or pillow. She said guards seized her glasses, rendering her all but unable to see. The lights in the cell were constantly on, and during daily interrogations, which lasted for hours, she was blindfolded and had to sit facing a wall, she said.

Are foreign prisoners held at Evin?

Iran has used the detention of foreign and dual citizens as a tool of its foreign policy for nearly five decades. Britain, France, the United States and others have accused Iran of detaining their citizens, as well as dual nationals, and using them as diplomatic bargaining chips.

Cécile Kohler and Jacques Paris, two French citizens, were held for over three years at Evin. Their detention has become a sticking point in relations between France and Iran.

Kohler, 40, a literature professor, and her partner, Paris, a retired professor in his 70s, were visiting Iran as tourists in 2022 when they were arrested on spying charges that France strenuously rejects. Other French citizens arrested on similar charges have been gradually released, leaving Kohler and Paris as the only French citizens remaining in Iranian custody.

French authorities have likened the conditions they face in Evin to "torture," saying they are in near total isolation and have almost no access to consular visits. Last month, France filed a complaint against Iran at the International Court of Justice over their case.

French Foreign Minister Jean-Noël Barrot said Monday that Kohler and Paris were unhurt after the Israeli strikes, which he called "unacceptable," and repeated France's demand for their release.