For more than two decades, Iran’s nuclear program has been one of the most pressing threats troubling decision-makers in Israel.
In confronting these threats, the Israeli intelligence agency Mossad has emerged as a powerful force in the covert battle to sabotage the project and prevent Tehran from obtaining a nuclear weapon.
Israel has adopted a “preemptive disruption” approach rather than merely pursuing a containment policy. For more than ten years, it has targeted the program from within through various means: assassinating scientists, launching cyberattacks, stealing secret documents, and recruiting local agents—before moving to direct targeting during its war with Tehran in June.
Senior fellow at the Atlantic Council, Tom Warrick, told Alhurra that “the way Israel carries out its military operations inside Iran shows that Mossad has penetrated the Iranian security establishment deeply.”
“Israel has used every available means to gather intelligence on Iran’s nuclear program,” he added.
But questions remain: How successful has this strategy been in curbing Iran’s nuclear ambitions? How has Israel been able to reach so deeply into the heart of the program? And what has been Iran’s response?
Mossad penetration
During the June war, Israeli agents managed to pinpoint the bedrooms of Iranian nuclear scientists and military leaders, enabling extremely precise airstrikes that killed them, according to Israeli authorities.
Among the prominent scientists killed in those strikes were Mohammad Mehdi Tehranchi, president of Islamic Azad University, and Fereydoon Abbasi-Davani, former head of Iran’s Atomic Energy Organization.
In an interview with Alhurra on the subject, American investigative journalist Dan Raviv, host of the Mossad Files podcast, noted that in the months leading up to the war, Mossad had been gathering detailed information on the habits and locations of 11 nuclear scientists, particularly in the Tehran area.
“These files even included maps of the bedroom locations inside these men’s homes,” said Raviv, who was a correspondent for CBS News for over 40 years and authored several books on Israeli intelligence and security.
According to Raviv, in recent years Mossad has succeeded in building a network of “local agents” inside Iran.
“These are not Israelis but Iranians or people of other nationalities, recruited either with financial incentives or because of opposition to the regime.”
He described this network as a “foreign legion” remotely run by Mossad officers abroad.
Raviv believes that Mossad no longer needs to send Israelis into Iran, thanks to the success of running this number of agents.
It took Israel years of work and attacks before reaching the “zero hour” in June.
Between 2010 and 2012, at least five Iranian nuclear scientists were assassinated in Tehran and other cities, according to Iranian media.
Although Tehran directly accused Mossad, Israel never officially admitted to those operations.
Iranian nuclear facilities during that period were also subjected to cyberattacks, most notably the 2010 “Stuxnet” virus attack on the Natanz facility, which Iran blamed on Israel at the time.
Israeli media then reported that Mossad carried out the attack.
The attack is believed to have destroyed hundreds of centrifuges and delayed Iran’s nuclear program for months—possibly years.
“The Stuxnet cyberattack caused a major delay in Iran’s uranium enrichment program. While it didn’t destroy all the centrifuges at Natanz, replacing the damaged equipment and ensuring full security undoubtedly took several years,” said John Gilbert, an expert at the Center for Arms Control and Non-Proliferation in Washington, to Alhurra.
In 2018, Israeli Prime Minister Benjamin Netanyahu announced that Mossad had succeeded in stealing hundreds of documents and digital files from the Iranian nuclear program’s archive in Tehran—considered one of the boldest operations in Mossad’s history.
According to Western intelligence, those documents revealed hidden aspects of Iranian activities and prompted the United States to withdraw from the nuclear deal in 2018.
In 2020, Israel managed to kill Mohsen Fakhrizadeh, regarded as the architect of Iran’s nuclear program, using a remotely operated machine gun.
Western reports said Mossad employed advanced technologies, such as AI-enhanced facial recognition, to guide the gun, which was mounted by the roadside near Fakhrizadeh’s home.
Gilbert said, “Israel succeeded in recruiting a number of Iranian agents who provided extremely valuable information over a long period, taking advantage of shortcomings in Iran’s own security measures.”
What is happening inside Iran?
In response to Israel’s assassination of more than 30 nuclear scientists and researchers during the June war, Iran took broad countermeasures to protect what remains of its human capital.
Sources said Tehran is working to safeguard its remaining nuclear scientists by sending them into secret hideouts.
The move comes amid fears—fueled by Israeli briefings—that further assassinations of Iranian nuclear scientists and researchers may be imminent.
Behnam Ben Taleblu, a researcher at the Foundation for Defense of Democracies in Washington, said the regime’s efforts to protect its scientists are “logical… it is trying to protect the minds that could be used to produce a nuclear weapon.”
However, protecting them is no easy task, given the methods used in the recent assassinations.
According to Ben Taleblu, the regime faces “a real dilemma due to its long-standing deep penetration by Israeli security services, raising questions about whether their security protocols can remain undetected or unexposed.”
At the same time, Iran announced last week that it had executed one of its nuclear scientists on charges of facilitating the assassination of a colleague during the 12-day war in June by passing information to Israel.
Iranian television aired what it said were the confessions of Roozbeh Vadi, in which he stated that he had sent information on the Fordow and Natanz uranium enrichment facilities to Israel. Authorities claimed Vadi, who held a PhD in nuclear engineering from Amirkabir University of Technology, met Mossad agents five times while in Vienna, and was asked to open a cryptocurrency account to receive payment for his services.
Vadi said in the video that Mossad promised him a foreign passport if he continued cooperating for a long time.
Iran’s state media also displayed an academic paper presented at an Iranian nuclear conference in 2012, co-authored by Vadi along with Ahmad Zolfaghar and Abdolhamid Manouchehr—two nuclear scientists killed by Israel in June.
The paper identified Vadi as a nuclear researcher at the Atomic Energy Organization of Iran, the country’s top nuclear authority.
Whether these allegations are true or not, what was shown on Iranian television amounted to an embarrassing acknowledgment of the depth of Mossad’s penetration inside Iran.
Tom Warrick noted, “Iran occasionally arrests or executes people it accuses of spying for Israel or the United States. It’s nearly impossible to tell whether these accusations are based on actual evidence or are simply a way for the regime to find scapegoats.”
Dan Raviv added that his sources inside Mossad continually talk about their success in recruiting and training reliable non-Israeli agents, which may include individuals working inside Iran’s nuclear program.
Iran’s protection strategy?
Iran has adopted a multi-layered defensive strategy to shield its nuclear program from threats, including direct military strikes, assassinations, and cyberwarfare.
Physical fortification and deeply burying nuclear infrastructure form the cornerstone of Iran’s defense.
The Natanz nuclear facility, a central site for uranium enrichment, lies 40 to 50 meters underground, protected by 7.6 meters of reinforced concrete and an additional 22 meters of earth, making it resistant to most conventional airstrikes.
Similarly, the Fordow site was built deep inside a mountain near the city of Qom. It is believed to be buried 80 to 100 meters underground and protected by reinforced concrete.
This means Israel’s most capable bunker-buster bombs are insufficient to destroy the facility, requiring the use of U.S. bombs. In June, the United States targeted Fordow with two GBU-57 Massive Ordnance Penetrator bunker-busters.
It appears Iran anticipated those strikes and prepared in advance. A third secret site—known as “Axe Mountain”—emerged about two kilometers south of Natanz, at a depth possibly exceeding 100 meters.
This facility was still under construction at the time of the June 2025 strikes and was not targeted.
The secret site is believed to be deeper than Fordow, with enhanced defensive features such as multiple tunnel entrances, making it more difficult to neutralize with bombs.
The International Atomic Energy Agency inquired about activities at Axe Mountain last April, but Iranian officials refused to comment.
According to an August 6 report by the Center for Strategic and International Studies (CSIS), the site may contain 400 kilograms of Iranian uranium enriched to 60%.
The report noted that the existence and ongoing activity of this new site represents a major development in Iran’s defensive strategy, reflecting a policy of “full fortification” to ensure the survival of its nuclear program against future attacks.
The report also addressed the impact of losing Iranian scientists: “The loss of scientific personnel could have a profound effect on Iran’s nuclear program, as the targeted scientists possessed unwritten, experiential knowledge necessary for complex tasks such as operating centrifuges, integrating systems, or even producing nuclear weapons.”
It further noted that Iran’s efforts could take years of specialized training and experience to learn how to build and operate complex machinery, such as centrifuges used for uranium enrichment.
The report concluded that targeting senior leaders and scientists to “erode the nuclear knowledge base could be as effective as destroying facilities and equipment, potentially extending Iran’s rearmament and production timelines.”
In a May interview with Alhurra, former Israeli national security adviser Eyal Hulata explained his country’s strategy to undermine Iran’s nuclear program through three elements: enrichment facilities, material conversion mechanisms, and the weapons program itself.
“If the key scientists aren’t there and the nuclear facilities are damaged, it will be very difficult for them to make a bomb,” Hulata said.
John Gilbert broadly agrees.
He noted, “Israel’s actions to disrupt Iran’s nuclear program have spanned many years. Yet, even with its many successes, it’s unlikely that Iran’s ultimate ability to develop a nuclear weapon has been eliminated.”
“The assassination of a number of Iranian scientists was a long-term setback, but the knowledge base likely remains intact—meaning weapon development has been delayed, but not ended,” Gilbert told Alhurra.
Ghassan Taqi
صحفي متخصص في الشؤون العراقية، يعمل في مؤسسة الشرق الأوسط للإرسال MBN منذ عام 2015. عمل سنوات مع إذاعة "أوروبا الحرة" ومؤسسات إعلامية عراقية وعربية.
