ATHENS, Greece (AP) — One after another, Israel has taken out Iran’s top leaders.

First it was Supreme Leader Ayatollah Ali Khamenei, killed in the opening shots of the war. Now Ali Larijani, the secretary of Iran’s Supreme National Security Council who was considered one of the most powerful figures in the country, has also been killed. As have a raft of other top-ranking military and political leaders.

With so many top leadership figures taken out, who is now running Iran? Here is a look at the country’s power structure, what is known — and what is not.

Khamenei’s successor

Ultimate authority in Iran rests with the country’s supreme leader, who has sat at the apex of power since the creation of the Islamic Republic in 1979 after the revolution that overthrew the shah.

After Khamenei was killed, his son, 56-year-old Mojtaba Khamenei, was quickly named to replace him as Iran’s new supreme leader. A secretive figure, the younger Khamenei has not been seen in public since the airstrike killed his 86-year-old father.

The cleric had long been considered a contender for the post, despite never having been elected or appointed to a government position. The younger Khamenei maintains close ties to the country’s powerful paramilitary Revolutionary Guard.

His views are believed to be even more hard-line than those of his father. Officially, he is now in charge of Iran’s armed forces, and any decision regarding the country’s nuclear program rests with him.

But is he truly running Iran?

Israel says Iran’s leadership is in disarray

“I’m not sure who’s running Iran right now,” Israeli Prime Minister Benjamin Netanyahu said during a news conference Thursday night. “Mojtaba, the replacement ayatollah, has not shown his face. Have you seen him? We haven’t, and we can’t vouch for what exactly is happening there.”

Mojtaba Khamenei’s wife, Zahra Haddad Adel, was also killed in the Israeli strike that killed his father. U.S. and Israeli officials have suggested he was wounded in the same attack.

“Iran’s command and control structure is in utter chaos,” Netanyahu said.

Burcu Ozcelik, senior research fellow for Middle East security at the Royal United Services Institute, a United Kingdom-based defense and security think tank, said the elimination of so many of Iran’s top leaders will alter its theocracy — but that the change could be a gradual one.

“Leadership matters, and the loss of key decision-makers spanning politics, intelligence, internal security and (the) army will have transformative consequences,” Ozcelik said.

“The fixation on the terminology of ‘regime collapse’ is obscuring the fact that the regime is already changing” due to the strikes against the country and the killing of high-level leaders. But the full impact of the war on the country could take time to emerge, Ozcelik explained.

“We need to be prepared for change that may take years, not weeks or months.”

The Revolutionary Guard

For many analysts, true power now rests with Iran’s feared paramilitary Islamic Revolutionary Guard.

“The Revolutionary Guard is the state now,” said Ali Vaez, Iran project director at the International Crisis Group. Before the war, the country’s civilian leadership was “subservient entirely” to the supreme leader, he explained, while the Guard was the second-most powerful force in the country.

But now, with the elder Khamenei gone and his son not enjoying the same authority as his father, “it is really the Revolutionary Guards who are running the country.”

The Guard rose out of Iran’s 1979 Islamic Revolution as a force meant to protect the country’s Shiite cleric-overseen government. It later became enshrined in its constitution and operated parallel to Iran’s regular armed forces.

The Guard’s expeditionary Quds Force was key in creating what Iran describes as its “Axis of Resistance” against Israel and the United States. It backed Syria’s former President Bashar Assad, the Lebanese militant group Hezbollah, Yemen’s Houthi rebels and other armed groups in the region.

An independent military

Early on in the war, Iranian Foreign Minister Abbas Araghchi suggested the country’s military units were acting independently from central government control.

“Our … military units are now in fact independent and somehow isolated and they are acting based on instructions — you know, general instructions — given to them in advance,” Araghchi had said on Al Jazeera on March 1.

Pressed about Tehran’s attacks on other Gulf nations — such as Oman, which had acted as an intermediary for Iran in recent nuclear talks with the U.S. — he said: “What happened in Oman was not our choice. We have already told our … army, armed forces to be careful about the targets that they choose.”

“Multiple layers of leadership”

The possibility of an Israeli or a U.S. attack on Iran had long been in the cards. It was something the Islamic Republic had factored into its planning, setting up multiple contingency plans, Vaez said.

“I think the mistake in the U.S. and in Israel is that they ended up believing their own rhetoric that Iran is akin to a terrorist organization, that decapitating the regime or removing one or two layers of political elite would result in paralysis and collapse,” Vaez said. “Whereas this is a state, … it has multiple layers of leadership.”

Even if all top generals are eliminated, he said, others lower down the ranks can pick up where their superiors left off. “The expectation that this regime will … implode by removing a few dozen senior leaders, I think is nothing but an illusion.”